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1.
J Agric Food Chem ; 72(23): 13431-13438, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38815265

ABSTRACT

In order to speculate the three-dimensional structure of the potential binding pocket of the chitin synthase inhibitor, a series of 2,4-diphenyloxazoline derivatives with different lengths of alkyl chains and heteroatoms were designed and synthesized by a homologous strategy. The bioassay results indicate that both the length of the alkyl chains and the type of substituents can affect the acaricidal activity against mite eggs. Compounds containing chloropropyl, alkoxyalkyl, and para-substituted phenoxyalkyl or phenylthioalkyl groups exhibit good activity, while those containing steric hindrance substituents or carbonyl substituents on the benzene ring exhibit reduced activity. Three-dimensional quantitative structure-activity relationship (3D-QSAR) study showed that there may be a narrow hydrophobic region deep in the pocket, and the steric effect plays a more important role than the electrostatic effect. The current work will provide assistance for future molecular design and target binding research.


Subject(s)
Acaricides , Quantitative Structure-Activity Relationship , Acaricides/chemistry , Acaricides/pharmacology , Animals , Mites/drug effects , Mites/chemistry , Oxazoles/chemistry , Oxazoles/pharmacology , Drug Design , Molecular Structure , Chitin Synthase/chemistry , Chitin Synthase/antagonists & inhibitors , Chitin Synthase/metabolism
2.
Science ; 383(6684): eadk3468, 2024 Feb 16.
Article in English | MEDLINE | ID: mdl-38359131

ABSTRACT

Plant intracellular nucleotide-binding leucine-rich repeat receptors (NLRs) analyzed to date oligomerize and form resistosomes upon activation to initiate immune responses. Some NLRs are encoded in tightly linked co-regulated head-to-head genes whose products function together as pairs. We uncover the oligomerization requirements for different Arabidopsis paired CHS3-CSA1 alleles. These pairs form resting-state heterodimers that oligomerize into complexes distinct from NLRs analyzed previously. Oligomerization requires both conserved and allele-specific features of the respective CHS3 and CSA1 Toll-like interleukin-1 receptor (TIR) domains. The receptor kinases BAK1 and BIRs inhibit CHS3-CSA1 pair oligomerization to maintain the CHS3-CSA1 heterodimer in an inactive state. Our study reveals that paired NLRs hetero-oligomerize and likely form a distinctive "dimer of heterodimers" and that structural heterogeneity is expected even among alleles of closely related paired NLRs.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Chitin Synthase , NLR Proteins , Plant Diseases , Plant Immunity , Receptors, Immunologic , Alleles , Arabidopsis/genetics , Arabidopsis/immunology , Arabidopsis Proteins/chemistry , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Chitin Synthase/chemistry , Chitin Synthase/genetics , Chitin Synthase/metabolism , Mutation , NLR Proteins/chemistry , NLR Proteins/genetics , NLR Proteins/metabolism , Plant Diseases/genetics , Plant Diseases/immunology , Plant Immunity/genetics , Receptors, Immunologic/chemistry , Receptors, Immunologic/genetics , Receptors, Immunologic/metabolism , Protein Multimerization
3.
Nat Commun ; 14(1): 4776, 2023 08 08.
Article in English | MEDLINE | ID: mdl-37553334

ABSTRACT

Chitin is one of the most abundant natural biopolymers and serves as a critical structural component of extracellular matrices, including fungal cell walls and insect exoskeletons. As a linear polymer of ß-(1,4)-linked N-acetylglucosamine, chitin is synthesized by chitin synthases, which are recognized as targets for antifungal and anti-insect drugs. In this study, we determine seven different cryo-electron microscopy structures of a Saccharomyces cerevisiae chitin synthase in the absence and presence of glycosyl donor, acceptor, product, or peptidyl nucleoside inhibitors. Combined with functional analyses, these structures show how the donor and acceptor substrates bind in the active site, how substrate hydrolysis drives self-priming, how a chitin-conducting transmembrane channel opens, and how peptidyl nucleoside inhibitors inhibit chitin synthase. Our work provides a structural basis for understanding the function and inhibition of chitin synthase.


Subject(s)
Chitin Synthase , Chitin , Chitin Synthase/chemistry , Chitin Synthase/metabolism , Chitin/metabolism , Cryoelectron Microscopy , Nucleosides/metabolism , Saccharomyces cerevisiae/metabolism , Catalysis
4.
Chembiochem ; 24(16): e202300388, 2023 08 15.
Article in English | MEDLINE | ID: mdl-37253095

ABSTRACT

Glycosyltransferases (GTs) are a large and diverse group of enzymes responsible for catalyzing the formation of a glycosidic bond between a donor molecule, usually a monosaccharide, and a wide range of acceptor molecules, thus, playing critical roles in various essential biological processes. Chitin and cellulose synthases are two inverting processive integral membrane GTs, belonging to the type-2 family involved in the biosynthesis of chitin and cellulose, respectively. Herein, we report that bacterial cellulose and chitin synthases share an E-D-D-ED-QRW-TK active site common motif that is spatially co-localized. This motif is conserved among distant bacterial evolutionary species despite their low amino acid sequence and structural similarities between them. This theoretical framework offers a new perspective to the current view that bacterial cellulose and chitin synthases are substrate specific and that chitin and cellulose are organism specific. It lays the ground for future in vivo and in silico experimental assessment of cellulose synthase catalytic promiscuity against uridine diphosphate N-acetylglucosamine and chitin synthase against uridine diphosphate glucose, respectively.


Subject(s)
Cellulose , Chitin Synthase , Chitin Synthase/genetics , Chitin Synthase/chemistry , Chitin Synthase/metabolism , Catalytic Domain , Amino Acid Sequence , Bacteria/metabolism , Chitin
5.
Insect Biochem Mol Biol ; 141: 103718, 2022 02.
Article in English | MEDLINE | ID: mdl-34982980

ABSTRACT

Chitin is an aminopolysaccharide present in insects as a major structural component of the cuticle. However, current knowledge on the chitin biosynthetic machinery, especially its constituents and mechanism, is limited. Using three independent binding assays, including co-immunoprecipitation, split-ubiquitin membrane yeast two-hybrid assay, and pull-down assay, we demonstrate that choline transporter-like protein 2 (Ctl2) interacts with krotzkopf verkehrt (kkv) in Drosophila melanogaster. The global knockdown of Ctl2 by RNA interference (RNAi) induced lethality at the larval stage. Tissue-specific RNAi to silence Ctl2 in the tracheal system and in the epidermis of the flies resulted in lethality at the first larval instar. The knockdown of Ctl2 in wings led to shrunken wings containing accumulated fluid. Calcofluor White staining demonstrated reduced chitin content in the first longitudinal vein of Ctl2 knockdown wings. The pro-cuticle, which was thinner compared to wildtype, exhibited a reduced number of chitin laminar layers. Phylogenetic analyses revealed orthologues of Ctl2 in different insect orders with highly conserved domains. Our findings provide new insights into cuticle formation, wherein Ctl2 plays an important role as a chitin-synthase interacting protein.


Subject(s)
Chitin Synthase/genetics , Drosophila Proteins/genetics , Drosophila melanogaster/genetics , Membrane Transport Proteins/genetics , Wings, Animal/growth & development , Amino Acid Sequence , Animals , Chitin Synthase/chemistry , Chitin Synthase/metabolism , Drosophila Proteins/chemistry , Drosophila Proteins/metabolism , Drosophila melanogaster/growth & development , Drosophila melanogaster/metabolism , Epidermis/growth & development , Larva/genetics , Larva/growth & development , Membrane Transport Proteins/chemistry , Membrane Transport Proteins/metabolism , Phylogeny , Sequence Alignment
6.
Mol Phylogenet Evol ; 139: 106558, 2019 10.
Article in English | MEDLINE | ID: mdl-31288106

ABSTRACT

The oomycetes are filamentous eukaryotic microorganisms, distinct from true fungi, many of which act as crop or fish pathogens that cause devastating losses in agriculture and aquaculture. Chitin is present in all true fungi, but it occurs in only small amounts in some Saprolegniomycetes and it is absent in Peronosporomycetes. However, the growth of several oomycetes is severely impacted by competitive chitin synthase (CHS) inhibitors. Here, we shed light on the diversity, evolution and function of oomycete CHS proteins. We show by phylogenetic analysis of 93 putative CHSs from 48 highly diverse oomycetes, including the early diverging Eurychasma dicksonii, that all available oomycete genomes contain at least one putative CHS gene. All gene products contain conserved CHS motifs essential for enzymatic activity and form two Peronosporomycete-specific and six Saprolegniale-specific clades. Proteins of all clades, except one, contain an N-terminal microtubule interacting and trafficking (MIT) domain as predicted by protein domain databases or manual analysis, which is supported by homology modelling and comparison of conserved structural features from sequence logos. We identified at least three groups of CHSs conserved among all oomycete lineages and used phylogenetic reconciliation analysis to infer the dynamic evolution of CHSs in oomycetes. The evolutionary aspects of CHS diversity in modern-day oomycetes are discussed. In addition, we observed hyphal tip rupture in Phytophthora infestans upon treatment with the CHS inhibitor nikkomycin Z. Combining data on phylogeny, gene expression, and response to CHS inhibitors, we propose the association of different CHS clades with certain developmental stages.


Subject(s)
Chitin Synthase/genetics , Evolution, Molecular , Genetic Variation , Oomycetes/enzymology , Oomycetes/genetics , Amino Acid Sequence , Chitin Synthase/chemistry , Conserved Sequence/genetics , Likelihood Functions , Phylogeny , Protein Domains
7.
Comput Biol Chem ; 80: 168-176, 2019 Jun.
Article in English | MEDLINE | ID: mdl-30965174

ABSTRACT

The alarm is rang for friendly fire; Saccharomyces cerevisiae (S. cerevisiae) newfound as a fungal pathogen with an individual feature. S. cerevisiae has food safety and is not capable of producing infection but, when the host defenses are weakened, there is room for opportunistic S. cerevisiae strains to cause a health issues. Fungal diseases are challenging to treat because, unlike bacteria, the fungal are eukaryotes. Antibiotics only target prokaryotic cells, whereas compounds that kill fungi also harm the mammalian host. Small differences between mammalian and fungal cells regarding genes and proteins sequence and function make finding a drug target more challenging. Recently, Chitin synthase has been considered as a promising target for antifungal drug development as it is absent in mammals. In S. cerevisiae, CHS3, a class IV chitin synthase, produces 90% of the chitin and essential for cell growth. CHS3 from the trans-Golgi network to the plasma membrane requires assembly of the exomer complex (including proteins cargo such as CHS5, CHS6, Bach1, and Arf1). In this work, we performed SELEX (Systematic Evolution of Ligands by EXponential enrichment) as high throughput virtual screening of the RCSB data bank to find an aptamer as potential inhibit of the class IV chitin synthase of S. cerevisiae. Among all the candidates, G-rich VEGF (GVEGF) aptamer (PDB code: 2M53) containing locked sugar parts was observed as potential inhibitor of the assembly of CHS5-CHS6 exomer complex a subsequently block the chitin biosynthesis pathway as an effective anti-fungal. It was suggested from the simulation that an assembly of exomer core should begin CHS5-CHS6, not from CHS5-Bach1. It is notable that secondary structures of CHS6 and Bach1 was observed very similar, but they have only 25% identity at the amino acid sequence that exhibited different features in exomer assembly.


Subject(s)
Adaptor Proteins, Vesicular Transport/metabolism , Aptamers, Nucleotide/metabolism , Chitin Synthase/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Membrane Proteins/metabolism , Protein Multimerization/drug effects , Saccharomyces cerevisiae Proteins/metabolism , Vascular Endothelial Growth Factor A/chemistry , Adaptor Proteins, Vesicular Transport/chemistry , Amino Acid Sequence , Antifungal Agents/metabolism , Aptamers, Nucleotide/genetics , Binding Sites , Chitin Synthase/chemistry , G-Quadruplexes , Intracellular Signaling Peptides and Proteins/chemistry , Membrane Proteins/chemistry , Molecular Docking Simulation , Protein Binding , SELEX Aptamer Technique , Saccharomyces cerevisiae/enzymology , Saccharomyces cerevisiae Proteins/chemistry , Sequence Alignment
8.
Sci Rep ; 9(1): 1087, 2019 01 31.
Article in English | MEDLINE | ID: mdl-30705372

ABSTRACT

Chitin synthase is responsible for chitin synthesis in the cuticles and cuticular linings of other tissues in insects. We cloned two alternative splicing variants of the chitin synthase 1 gene (SfCHS1) from the white-backed planthopper, Sogatella furcifera. The full-length cDNA of the two variants (SfCHS1a and SfCHS1b) consists of 6408 bp, contains a 4719-bp open reading frame encoding 1572 amino acids, and has 5' and 3' non-coding regions of 283 and 1406 bp, respectively. The two splicing variants occur at the same position in the cDNA sequence between base pairs 4115 and 4291, and consist of 177 nucleotides that encode 59 amino acids but show 74.6% identity at the amino acid level. Analysis in different developmental stages showed that expression of SfCHS1 and SfCHS1a were highest just after molting, whereas SfCHS1b reached its highest expression level 2 days after molting. Further, SfCHS1 and SfCHS1a were mainly expressed in the integument, whereas SfCHS1b was predominately expressed in the gut and fat body. RNAi-based gene silencing inhibited transcript levels of the corresponding mRNAs in S. furcifera nymphs injected with double-stranded RNA of SfCHS1, SfCHS1a, and SfCHS1b, resulted in malformed phenotypes, and killed most of the treated nymphs. Our results indicate that SfCHS1 may be a potential target gene for RNAi-based S. furcifera control.


Subject(s)
Alternative Splicing , Chitin Synthase , Cloning, Molecular , Gene Expression , Hemiptera , Insect Proteins , Animals , Chitin Synthase/biosynthesis , Chitin Synthase/chemistry , Chitin Synthase/genetics , Chitin Synthase/isolation & purification , Hemiptera/enzymology , Hemiptera/genetics , Insect Proteins/biosynthesis , Insect Proteins/chemistry , Insect Proteins/genetics , Insect Proteins/isolation & purification , Isoenzymes/biosynthesis , Isoenzymes/chemistry , Isoenzymes/genetics , Isoenzymes/isolation & purification , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/isolation & purification
9.
Int J Mol Sci ; 18(4)2017 Mar 25.
Article in English | MEDLINE | ID: mdl-28346351

ABSTRACT

Chitin biosynthesis in yeast is accomplished by three chitin synthases (Chs) termed Chs1, Chs2 and Chs3, of which the latter accounts for most of the chitin deposited within the cell wall. While the overall structures of Chs1 and Chs2 are similar to those of other chitin synthases from fungi and arthropods, Chs3 lacks some of the C-terminal transmembrane helices raising questions regarding its structure and topology. To fill this gap of knowledge, we performed bioinformatic analyses and protease protection assays that revealed significant information about the catalytic domain, the chitin-translocating channel and the interfacial helices in between. In particular, we identified an amphipathic, crescent-shaped α-helix attached to the inner side of the membrane that presumably controls the channel entrance and a finger helix pushing the polymer into the channel. Evidence has accumulated in the past years that chitin synthases form oligomeric complexes, which may be necessary for the formation of chitin nanofibrils. However, the functional significance for living yeast cells has remained elusive. To test Chs3 oligomerization in vivo, we used bimolecular fluorescence complementation. We detected oligomeric complexes at the bud neck, the lateral plasma membrane, and in membranes of Golgi vesicles, and analyzed their transport route using various trafficking mutants.


Subject(s)
Chitin Synthase/chemistry , Saccharomyces cerevisiae Proteins/chemistry , Catalytic Domain , Chitin Synthase/genetics , Chitin Synthase/metabolism , Protein Binding , Protein Multimerization , Saccharomyces cerevisiae/enzymology , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/metabolism
10.
FEBS J ; 283(16): 3072-88, 2016 08.
Article in English | MEDLINE | ID: mdl-27363606

ABSTRACT

UNLABELLED: Chitin synthases (Chs) are responsible for the synthesis of chitin, a key structural cell wall polysaccharide in many organisms. They are essential for growth in certain oomycete species, some of which are pathogenic to diverse higher organisms. Recently, a microtubule interacting and trafficking (MIT) domain, which is not found in any fungal Chs, has been identified in some oomycete Chs proteins. Based on experimental data relating to the binding specificity of other eukaryotic MIT domains, there was speculation that this domain may be involved in the intracellular trafficking of Chs proteins. However, there is currently no evidence for this or any other function for the MIT domain in these enzymes. To attempt to elucidate their function, MIT domains from two Chs enzymes from the oomycete Saprolegnia monoica were cloned, expressed, and characterized. Both were shown to interact strongly with the plasma membrane component, phosphatidic acid, and to have additional putative interactions with proteins thought to be involved in protein transport and localization. Aiding our understanding of these data, the structure of the first MIT domain from a carbohydrate-active enzyme (MIT1) was solved by NMR, and a model structure of a second MIT domain (MIT2) was built by homology modeling. Our results suggest a potential function for these MIT domains in the intracellular transport and/or regulation of Chs enzymes in the oomycetes. DATABASE: Structural data are available in the Biological Magnetic Resonance Bank (BMRB) database under the accession number 19987 and the PDB database under the accession number 2MPK.


Subject(s)
Chitin Synthase/chemistry , Chitin Synthase/metabolism , Saprolegnia/enzymology , Adaptor Protein Complex 3/metabolism , Circular Dichroism , Microtubules/metabolism , Models, Molecular , Nuclear Magnetic Resonance, Biomolecular , Phospholipids/metabolism , Protein Domains , Protein Interaction Domains and Motifs , Structural Homology, Protein
11.
Arch Insect Biochem Physiol ; 92(4): 242-58, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27030662

ABSTRACT

Chitin synthase (ChS) plays a critical role in chitin synthesis and excretion. In this study, two ChS genes (LdChSA and LdChSB) were identified in Leptinotarsa decemlineata. LdChSA contains two splicing variants, LdChSAa and LdChSAb. Within the first, second, and third larval instars, the mRNA levels of LdChSAa, LdChSAb, and LdChSB coincide with the peaks of circulating 20-hydroxyecdysone (20E) and juvenile hormone (JH). In vitro culture of midguts and an in vivo bioassay revealed that 20E and an ecdysteroid agonist halofenozide stimulated the expression of the three LdChSs. Conversely, a reduction of 20E by RNA interference (RNAi) of an ecdysteroidogenesis gene LdSHD repressed the expression of these LdChSs, and ingestion of halofenozide by LdSHD RNAi larvae rescued the repression. Moreover, disruption of 20E signaling by RNAi of LdEcR, LdE75, LdHR3, and LdFTZ-F1 reduced the expression levels of these genes. Similarly, in vitro culture and an in vivo bioassay showed that exogenous JH and a JH analog methoprene activated the expression of the three LdChSs, whereas a decrease in JH by RNAi of a JH biosynthesis gene LdJHAMT downregulated these LdChSs. It seems that JH upregulates LdChSs at the early stage of each instar, whereas a 20E pulse triggers the transcription of LdChSs during molting in L. decemlineata.


Subject(s)
Chitin Synthase/genetics , Coleoptera/enzymology , Coleoptera/genetics , Gene Expression Regulation , Insect Proteins/genetics , Amino Acid Sequence , Animals , Chitin Synthase/chemistry , Chitin Synthase/metabolism , Cloning, Molecular , Coleoptera/classification , Coleoptera/growth & development , DNA, Complementary/genetics , DNA, Complementary/metabolism , Ecdysterone/metabolism , Insect Proteins/chemistry , Insect Proteins/metabolism , Isoenzymes/genetics , Juvenile Hormones/metabolism , Larva/enzymology , Larva/genetics , Larva/growth & development , Larva/metabolism , Phylogeny , RNA, Messenger/genetics , RNA, Messenger/metabolism , Real-Time Polymerase Chain Reaction , Sequence Alignment
12.
Phys Chem Chem Phys ; 18(7): 5281-90, 2016 Feb 21.
Article in English | MEDLINE | ID: mdl-26818595

ABSTRACT

The critical role of chitin synthases in oomycete hyphal tip growth has been established. A microtubule interacting and trafficking (MIT) domain was discovered in the chitin synthases of the oomycete model organism, Saprolegnia monoica. MIT domains have been identified in diverse proteins and may play a role in intracellular trafficking. The structure of the Saprolegnia monoica chitin synthase 1 (SmChs1) MIT domain has been recently determined by our group. However, although our in vitro assay identified increased strength in interactions between the MIT domain and phosphatidic acid (PA) relative to other phospholipids including phosphatidylcholine (PC), the mechanism used by the MIT domain remains unknown. In this work, the adsorption behavior of the SmChs1 MIT domain on POPA and POPC membranes was systematically investigated by molecular dynamics simulations. Our results indicate that the MIT domain can adsorb onto the tested membranes in varying orientations. Interestingly, due to the specific interactions between MIT residues and lipid molecules, the binding affinity to the POPA membrane is much higher than that to the POPC membrane. A binding hotspot, which is critical for the adsorption of the MIT domain onto the POPA membrane, was also identified. The lower binding affinity to the POPC membrane can be attributed to the self-saturated membrane surface, which is unfavorable for hydrogen-bond and electrostatic interactions. The present study provides insight into the adsorption profile of SmChs1 and additionally has the potential to improve our understanding of other proteins containing MIT domains.


Subject(s)
Chitin Synthase/metabolism , Membranes, Artificial , Phosphatidic Acids/metabolism , Phosphatidylcholines/metabolism , Saprolegnia/enzymology , Adsorption , Amino Acid Sequence , Chitin Synthase/chemistry , Molecular Dynamics Simulation , Molecular Sequence Data
13.
Glob Chang Biol ; 22(6): 2025-37, 2016 Jun.
Article in English | MEDLINE | ID: mdl-26644007

ABSTRACT

Future ocean acidification (OA) will affect physiological traits of marine species, with calcifying species being particularly vulnerable. As OA entails high energy demands, particularly during the rapid juvenile growth phase, food supply may play a key role in the response of marine organisms to OA. We experimentally evaluated the role of food supply in modulating physiological responses and biomineralization processes in juveniles of the Chilean scallop, Argopecten purpuratus, that were exposed to control (pH ~ 8.0) and low pH (pH ~ 7.6) conditions using three food supply treatments (high, intermediate, and low). We found that pH and food levels had additive effects on the physiological response of the juvenile scallops. Metabolic rates, shell growth, net calcification, and ingestion rates increased significantly at low pH conditions, independent of food. These physiological responses increased significantly in organisms exposed to intermediate and high levels of food supply. Hence, food supply seems to play a major role modulating organismal response by providing the energetic means to bolster the physiological response of OA stress. On the contrary, the relative expression of chitin synthase, a functional molecule for biomineralization, increased significantly in scallops exposed to low food supply and low pH, which resulted in a thicker periostracum enriched with chitin polysaccharides. Under reduced food and low pH conditions, the adaptive organismal response was to trade-off growth for the expression of biomineralization molecules and altering of the organic composition of shell periostracum, suggesting that the future performance of these calcifiers will depend on the trajectories of both OA and food supply. Thus, incorporating a suite of traits and multiple stressors in future studies of the adaptive organismal response may provide key insights on OA impacts on marine calcifiers.


Subject(s)
Animal Shells/physiology , Calcification, Physiologic , Food Chain , Pectinidae/physiology , Seawater/chemistry , Adaptation, Physiological , Animals , Chile , Chitin/chemistry , Chitin Synthase/chemistry , Climate Change , Hydrogen-Ion Concentration , Oceans and Seas , Oxygen Consumption
14.
Curr Opin Struct Biol ; 34: 78-86, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26342143

ABSTRACT

Complex carbohydrates perform essential functions in life, including energy storage, cell signaling, protein targeting, quality control, as well as supporting cell structure and stability. Extracellular polysaccharides (EPS) represent mainly structural polymers and are found in essentially all kingdoms of life. For example, EPS are important biofilm and capsule components in bacteria, represent major constituents in cell walls of fungi, algae, arthropods and plants, and modulate the extracellular matrix in vertebrates. Different mechanisms evolved by which EPS are synthesized. Here, we review the structures and functions of membrane-integrated processive glycosyltransferases (GTs) implicated in the synthesis and secretion of chitin, alginate, hyaluronan and poly-N-acetylglucosamine (PNAG).


Subject(s)
Glycosyltransferases/chemistry , Glycosyltransferases/metabolism , Membrane Proteins/chemistry , Membrane Proteins/metabolism , Animals , Biopolymers/chemistry , Biopolymers/metabolism , Chitin Synthase/chemistry , Chitin Synthase/metabolism , Humans , Molecular Weight , Polysaccharides/chemistry , Polysaccharides/metabolism , Protein Interaction Domains and Motifs , Protein Processing, Post-Translational , Structure-Activity Relationship
15.
Sci Rep ; 5: 11153, 2015 Jun 18.
Article in English | MEDLINE | ID: mdl-26084520

ABSTRACT

Plasmodiophora brassicae causes clubroot, a major disease of Brassica oil and vegetable crops worldwide. P. brassicae is a Plasmodiophorid, obligate biotrophic protist in the eukaryotic kingdom of Rhizaria. Here we present the 25.5 Mb genome draft of P. brassicae, developmental stage-specific transcriptomes and a transcriptome of Spongospora subterranea, the Plasmodiophorid causing powdery scab on potato. Like other biotrophic pathogens both Plasmodiophorids are reduced in metabolic pathways. Phytohormones contribute to the gall phenotypes of infected roots. We report a protein (PbGH3) that can modify auxin and jasmonic acid. Plasmodiophorids contain chitin in cell walls of the resilient resting spores. If recognized, chitin can trigger defense responses in plants. Interestingly, chitin-related enzymes of Plasmodiophorids built specific families and the carbohydrate/chitin binding (CBM18) domain is enriched in the Plasmodiophorid secretome. Plasmodiophorids chitin synthases belong to two families, which were present before the split of the eukaryotic Stramenopiles/Alveolates/Rhizaria/Plantae and Metazoa/Fungi/Amoebozoa megagroups, suggesting chitin synthesis to be an ancient feature of eukaryotes. This exemplifies the importance of genomic data from unexplored eukaryotic groups, such as the Plasmodiophorids, to decipher evolutionary relationships and gene diversification of early eukaryotes.


Subject(s)
Chitin Synthase/genetics , Chitin Synthase/metabolism , Genome, Protozoan , Life Cycle Stages , Plasmodiophorida/physiology , Biological Evolution , Carbohydrate Metabolism , Chitin Synthase/chemistry , Cluster Analysis , Genomics , High-Throughput Nucleotide Sequencing , Metabolome , Metabolomics , Models, Molecular , Multigene Family , Plant Growth Regulators/pharmacology , Plasmodiophorida/drug effects , Protein Conformation
16.
Genet Mol Res ; 14(4): 19264-74, 2015 Dec 29.
Article in English | MEDLINE | ID: mdl-26782579

ABSTRACT

The triangle sail mussel, Hyriopsis cumingii, is the most important freshwater pearl mussel in China. However, the mechanisms underlying its chitin-mediated shell and nacre formation remain largely unknown. Here, we characterized a chitin synthase (CS) gene (HcCS1) in H. cumingii, and analyzed its possible physiological function. The complete ORF sequence of HcCS1 contained 6903 bp, encoding a 2300-amino acid protein (theoretical molecular mass = 264 kDa; isoelectric point = 6.22), and no putative signal peptide was predicted. A myosin motor head domain, a CS domain, and 12 transmembrane domains were found. The predicted spatial structures of the myosin head and CS domains were similar to the electron microscopic structure of the heavy meromyosin subfragment of chicken smooth muscle myosin and the crystal structure of bacterial cellulose synthase, respectively. This structural similarity indicates that the functions of these two domains might be conserved. Quantitative reverse transcription PCR results showed that HcCS1 was present in all detected tissues, with the highest expression levels detected in the mantle. The HcCS1 transcripts in the mantle were upregulated following shell damage from 12 to 24 h post-damage, and they peaked (approximately 1.5-fold increase) at 12 h after shell damage. These findings suggest that HcCS1 was involved in shell regeneration, and that it might participate in shell and nacre formation in this species via chitin synthesis. HcCS1 might also dynamically regulate chitin deposition during the process of shell and nacre formation with the help of its conserved myosin head domain.


Subject(s)
Animal Shells/metabolism , Bivalvia/genetics , Chitin Synthase/genetics , Chitin/biosynthesis , Nacre/metabolism , Amino Acid Sequence , Animals , Bivalvia/classification , Bivalvia/enzymology , Chickens , Chitin Synthase/chemistry , Chitin Synthase/metabolism , Fresh Water , Gene Expression , Glucosyltransferases/chemistry , Glucosyltransferases/genetics , Isoelectric Point , Models, Molecular , Molecular Sequence Data , Molecular Weight , Myosin Subfragments/chemistry , Myosin Subfragments/genetics , Open Reading Frames , Phylogeny , Protein Structure, Secondary , Protein Structure, Tertiary , Sequence Alignment , Structural Homology, Protein
17.
PLoS One ; 9(8): e104920, 2014.
Article in English | MEDLINE | ID: mdl-25148134

ABSTRACT

The cell wall is a protective and versatile structure distributed in all fungi. The component responsible for its rigidity is chitin, a product of chitin synthase (Chsp) enzymes. There are seven classes of chitin synthase genes (CHS) and the amount and type encoded in fungal genomes varies considerably from one species to another. Previous Chsp sequence analyses focused on their study as individual units, regardless of genomic context. The identification of blocks of conserved genes between genomes can provide important clues about the interactions and localization of chitin synthases. On the present study, we carried out an in silico search of all putative Chsp encoded in 54 full fungal genomes, encompassing 21 orders from five phyla. Phylogenetic studies of these Chsp were able to confidently classify 347 out of the 369 Chsp identified (94%). Patterns in the distribution of Chsp related to taxonomy were identified, the most prominent being related to the type of fungal growth. More importantly, a synteny analysis for genomic blocks centered on class IV Chsp (the most abundant and widely distributed Chsp class) identified a putative cell wall metabolism gene cluster in members of the genus Aspergillus, the first such association reported for any fungal genome.


Subject(s)
Aspergillus/genetics , Aspergillus/metabolism , Cell Wall/metabolism , Chitin Synthase/genetics , Genome, Fungal , Multigene Family , Phylogeny , Amino Acid Motifs , Amino Acid Sequence , Chitin Synthase/chemistry , Chitin Synthase/classification , Cluster Analysis , Computational Biology , Conserved Sequence , Fungal Proteins/chemistry , Fungal Proteins/genetics , Fungal Proteins/metabolism , Gene Expression Regulation, Fungal , Gene Order
18.
J Biol Chem ; 289(33): 23020-23028, 2014 Aug 15.
Article in English | MEDLINE | ID: mdl-24942743

ABSTRACT

Chitin synthases (CHS) produce chitin, an essential component of the fungal cell wall. The molecular mechanism of processive chitin synthesis is not understood, limiting the discovery of new inhibitors of this enzyme class. We identified the bacterial glycosyltransferase NodC as an appropriate model system to study the general structure and reaction mechanism of CHS. A high throughput screening-compatible novel assay demonstrates that a known inhibitor of fungal CHS also inhibit NodC. A structural model of NodC, on the basis of the recently published BcsA cellulose synthase structure, enabled probing of the catalytic mechanism by mutagenesis, demonstrating the essential roles of the DD and QXXRW catalytic motifs. The NodC membrane topology was mapped, validating the structural model. Together, these approaches give insight into the CHS structure and mechanism and provide a platform for the discovery of inhibitors for this antifungal target.


Subject(s)
Bacterial Proteins , Chitin Synthase , Chitin , Models, Biological , Models, Molecular , Sinorhizobium meliloti/enzymology , Amino Acid Motifs , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Chitin/biosynthesis , Chitin/chemistry , Chitin Synthase/chemistry , Chitin Synthase/metabolism , Glucosyltransferases/chemistry , Glucosyltransferases/metabolism
19.
Genome Biol Evol ; 6(2): 316-25, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24443419

ABSTRACT

Even though chitin is one of the most abundant biopolymers in nature, current knowledge on chitin formation is largely based only on data from fungi and insects. This study reveals unanticipated broad taxonomic distribution and extensive diversification of chitin synthases (CSs) in Metazoa, shedding new light on the relevance of chitin in animals and suggesting unforeseen complexity of chitin synthesis in many groups. We uncovered robust orthologs to insect type CSs in several representatives of deuterostomes, which generally are not thought to possess chitin. This suggests a broader distribution and function of chitin in this branch of the animal kingdom. We characterize a new CS type present not only in basal metazoans such as sponges and cnidarians but also in several bilaterian representatives. The most extensive diversification of CSs took place during emergence of lophotrochozoans, the third large group of protostomes next to arthropods and nematodes, resulting in coexistence of up to ten CS paralogs in molluscs. Independent fusion to different kinds of myosin motor domains in fungi and lophotrochozoans points toward high relevance of CS interaction with the cytoskeleton for fine-tuned chitin secretion. Given the fundamental role that chitin plays in the morphology of many animals, the here presented CS diversification reveals many evolutionary complexities. Our findings strongly suggest a very broad and multifarious occurrence of chitin and question an ancestral role as cuticular component. The molecular mechanisms underlying regulation of animal chitin synthesis are most likely far more complex and diverse than existing data from insects suggest.


Subject(s)
Chitin Synthase/genetics , Eukaryota/enzymology , Eukaryota/genetics , Evolution, Molecular , Genetic Variation , Amino Acid Sequence , Animals , Chitin Synthase/chemistry , Eukaryota/chemistry , Eukaryota/classification , Insecta/chemistry , Insecta/classification , Insecta/enzymology , Insecta/genetics , Molecular Sequence Data , Phylogeny , Protein Structure, Tertiary
20.
Biomed Res Int ; 2013: 169794, 2013.
Article in English | MEDLINE | ID: mdl-24069589

ABSTRACT

During anti-Malassezia screening of plants by CLSI broth microdilution method, Cladia aggregata (Swartz) Nyl. (family Cladoniaceae), a fruticose lichen from Sikkim (northeast Himalayan region), has been found effective at minimum inhibitory concentrations (mg/mL) of 2.72, 0.63, and 1.28 against yeast-like fungi namely, M. furfur, M. globosa and M. sympodialis, respectively. These test pathogens are responsible for pityriasis versicolor (PV) and seborrheic dermatitis (SD) in humans. We tried to establish the reason for variable MICs against various Malassezia spp. using bioinformatical tools, thereby reducing the cost of the experimentation. This is the first report on anti-Malassezia activity of C. aggregata and thus can serve as a potential source for the development of cosmaceuticals.


Subject(s)
Cosmetics/pharmacology , Lichens/physiology , Malassezia/drug effects , Phylogeny , Amino Acid Sequence , Animals , Antifungal Agents/metabolism , Chitin Synthase/chemistry , Fluconazole/pharmacology , Humans , Lichens/chemistry , Microbial Sensitivity Tests , Molecular Sequence Data
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