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1.
Int J Antimicrob Agents ; : 107171, 2024 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-38588869

RESUMO

Stenotrophomonas spp. intrinsically resistant to many ß-lactam antibiotics are found throughout the environment. CESS-1 identified in Stenotrophomonas sp. KCTC 12332 is an uncharacterized class A ß-lactamase. Here, CESS-1 was revealed to display hydrolytic activities toward penicillins (penicillin G and ampicillin) and cephalosporins (cephalexin, cefaclor, and cefotaxime), while its activity toward carbapenems (imipenem and meropenem) was negligible. Although cefaclor, cephalexin, and ampicillin have similar structures with identical R1 side chains, the catalytic parameters of CESS-1 toward the three ß-lactam antibiotics were distinct. The kcat values for cefaclor, cephalexin, and ampicillin were calculated to be 1249.6 s-1, 204.3 s-1, and 69.8 s-1, respectively, with the accompanying KM values of 287.6 µM, 236.7 µM, and 28.8 µM, respectively. Remarkably, CESS-1 discriminates cefaclor and cephalexin with only one structural difference: -Cl (cefaclor) and -CH3 (cephalexin) at C3. According to structural comparisons among three E166Q mutants of CESS-1 acylated by cefaclor, cephalexin, and ampicillin, the cooperative positional changes of the R1 side chain of substrates and its contacting ß5-ß6 loop affect the distance between Asn170 and the deacylating water at the acyl-enzyme intermediate state. This is directly associated with the differential hydrolytic activities of CESS-1 toward the three structurally similar ß-lactam antibiotics.

2.
Biomaterials ; 308: 122539, 2024 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-38552366

RESUMO

Catechol-based biomaterials demonstrate biocompatibility, making them suitable for a wide range of therapeutic applications when integrated into various molecular frameworks. However, the development of orally available catechol-based biomaterials has been hindered by significant pH variations and complex interactions in the gastrointestinal (GI) tract. In this study, we introduce a novel catechol-modified bile acid (CMBA), which is synthesized by anchoring the FDA-approved drug, ursodeoxycholic acid to the neurotransmitter dopamine. This modification could form a new apical sodium-dependent bile acid transporter (ASBT) inhibitor (ASBTi) due to the bile acid moiety. The computational analysis using the TRAnsient Pockets in Proteins (TRAPP) module, coupled with MD simulations, revealed that CMBA exhibits a strong binding affinity at residues 51-55 of ASBT with a low inhibitory constant (Ki) value. Notably, in slightly alkaline biological conditions, CMBA molecules self-assemble into carrier-free nanoparticles with an average size of 240.2 ± 44.2 nm, while maintaining their ability to bind with ASBT. When administered orally, CMBA accumulates in the ileum and liver over 24 h, exhibiting significant therapeutic effects on bile acid (BA) metabolism in a high-fat diet (HFD)-fed mouse model. This study underscores the therapeutic potential of the newly developed catechol-based, pH-responsive ASBT-inhibiting nanoparticles presenting a promising avenue for advancing therapy.

3.
PLoS One ; 19(3): e0298999, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38526988

RESUMO

Sulfurtransferases transfer of sulfur atoms from thiols to acceptors like cyanide. They are categorized as thiosulfate sulfurtransferases (TSTs) and 3-mercaptopyruvate sulfurtransferases (MSTs). TSTs transfer sulfur from thiosulfate to cyanide, producing thiocyanate. MSTs transfer sulfur from 3-mercaptopyruvate to cyanide, yielding pyruvate and thiocyanate. The present study aimed to isolate and characterize the sulfurtransferase FrST from Frondihabitans sp. PAMC28461 using biochemical and structural analyses. FrST exists as a dimer and can be classified as a TST rather than an MST according to sequence-based clustering and enzyme activity. Furthermore, the discovery of activity over a wide temperature range and the broad substrate specificity exhibited by FrST suggest promising prospects for its utilization in industrial applications, such as the detoxification of cyanide.


Assuntos
Cisteína/análogos & derivados , Tiocianatos , Tiossulfatos , Sulfurtransferases/química , Tiossulfato Sulfurtransferase , Ácido Pirúvico , Cianetos , Enxofre
4.
Int J Biol Macromol ; 264(Pt 1): 130419, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38423431

RESUMO

Epoxide hydrolases (EHs), which catalyze the transformation of epoxides to diols, are present in many eukaryotic and prokaryotic organisms. They have recently drawn considerable attention from organic chemists owing to their application in the semisynthesis of enantiospecific diol compounds. Here, we report the crystal structures of BoEH from Bosea sp. PAMC 26642 and CaEH from Caballeronia sordidicola PAMC 26510 at 1.95 and 2.43 Å resolution, respectively. Structural analysis showed that the overall structures of BoEH and CaEH commonly possess typical α/ß hydrolase fold with the same ring-opening residues (Tyr-Tyr) and conserved catalytic triad residues (Asp-Asp-His). However, the two enzymes were found to have significantly different sequence compositions in the cap domain region, which is involved in the formation of the substrate-binding site in both enzymes. Enzyme activity assay results showed that BoEH had the strongest activity toward the linear aliphatic substrates, whereas CaEH had a higher preference for aromatic- and cycloaliphatic substrates. Computational docking simulations and tunnel identification revealed important residues with different substrate-binding preferences. Collectively, structure comparison studies, together with ligand docking simulation results, suggested that the differences in substrate-binding site residues were highly correlated with substrate specificity.


Assuntos
Bactérias , Epóxido Hidrolases , Epóxido Hidrolases/química , Sítios de Ligação , Catálise , Bactérias/metabolismo , Especificidade por Substrato
5.
Sci Rep ; 14(1): 3234, 2024 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-38331970

RESUMO

Many polar organisms produce antifreeze proteins (AFPs) and ice-binding proteins (IBPs) to protect themselves from ice formation. As IBPs protect cells and organisms, the potential of IBPs as natural or biological cryoprotective agents (CPAs) for the cryopreservation of animal cells, such as oocytes and sperm, has been explored to increase the recovery rate after freezing-thawing. However, only a few IBPs have shown success in cryopreservation, possibly because of the presence of protein denaturants, such as dimethyl sulfoxide, alcohols, or ethylene glycol, in freezing buffer conditions, rendering the IBPs inactive. Therefore, we investigated the thermal and chemical stability of FfIBP isolated from Antarctic bacteria to assess its suitability as a protein-based impermeable cryoprotectant. A molecular dynamics (MD) simulation identified and generated stability-enhanced mutants (FfIBP_CC1). The results indicated that FfIBP_CC1 displayed enhanced resistance to denaturation at elevated temperatures and chemical concentrations, compared to wildtype FfIBP, and was functional in known CPAs while retaining ice-binding properties. Given that FfIBP shares an overall structure similar to DUF3494 IBPs, which are recognized as the most widespread IBP family, these findings provide important structural information on thermal and chemical stability, which could potentially be applied to other DUF3494 IBPs for future protein engineering.


Assuntos
Proteínas de Transporte , Gelo , Masculino , Animais , Proteínas de Transporte/metabolismo , Sêmen/metabolismo , Bactérias/metabolismo , Congelamento , Proteínas Anticongelantes/química , Crioprotetores/farmacologia , Crioprotetores/metabolismo
6.
Sci Rep ; 14(1): 1342, 2024 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-38228797

RESUMO

Cladonia borealis is a lichen that inhabits Antarctica's harsh environment. We sequenced the whole genome of a C. borealis culture isolated from a specimen collected in Antarctica using long-read sequencing technology to identify specific genetic elements related to its potential environmental adaptation. The final genome assembly produced 48 scaffolds, the longest being 2.2 Mbp, a 1.6 Mbp N50 contig length, and a 36 Mbp total length. A total of 10,749 protein-coding genes were annotated, containing 33 biosynthetic gene clusters and 102 carbohydrate-active enzymes. A comparative genomics analysis was conducted on six Cladonia species, and the genome of C. borealis exhibited 45 expanded and 50 contracted gene families. We identified that C. borealis has more Copia transposable elements and expanded transporters (ABC transporters and magnesium transporters) compared to other Cladonia species. Our results suggest that these differences contribute to C. borealis' remarkable adaptability in the Antarctic environment. This study also provides a useful resource for the genomic analysis of lichens and genetic insights into the survival of species isolated from Antarctica.


Assuntos
Ascomicetos , Líquens , Líquens/genética , Regiões Antárticas , Genoma , Ambientes Extremos , Filogenia
7.
Microorganisms ; 12(1)2024 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-38257947

RESUMO

In this study, Mesorhizobium sp. PAMC28654 was isolated from a soil sample collected from the polar region of Uganda. Whole-genome sequencing and comparative genomics were performed to better understand the genomic features necessary for Mesorhizobium sp. PAMC28654 to survive and thrive in extreme conditions and stresses. Additionally, diverse sequence analysis tools were employed for genomic investigation. The results of the analysis were then validated using wet-lab experiments. Genome analysis showed trace elements' resistant proteins (CopC, CopD, CzcD, and Acr3), exopolysaccharide (EPS)-producing proteins (ExoF and ExoQ), and nitrogen metabolic proteins (NarG, NarH, and NarI). The strain was positive for nitrate reduction. It was tolerant to 100 mM NaCl at 15 °C and 25 °C temperatures and resistant to multiple trace elements (up to 1 mM CuSO4·5H2O, 2 mM CoCl2·6H2O, 1 mM ZnSO4·7H2O, 0.05 mM Cd(NO3)2·4H2O, and 100 mM Na2HAsO4·7H2O at 15 °C and 0.25 mM CuSO4·5H2O, 2 mM CoCl2·6H2O, 0.5 mM ZnSO4·7H2O, 0.01 mM Cd(NO3)2·4H2O, and 100 mM Na2HAsO4·7H2O at 25 °C). This research contributes to our understanding of bacteria's ability to survive abiotic stresses. The isolated strain can be a potential candidate for implementation for environmental and agricultural purposes.

8.
Front Microbiol ; 14: 1280775, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37920266

RESUMO

Glaciimonas sp. PAMC28666, an extremophilic bacterium thriving in Antarctic soil and belonging to the Oxalobacteraceae family, represents the only complete genome of its genus available in the NCBI database. Its genome measures 5.2 Mb and comprises 4,476 genes (4,350 protein-coding and 72 non-coding). Phylogenetic analysis shows the strain PAMC28666 in a unique branch within the genus Glaciimonas, closely related to Glaciimonas alpine Cr9-12, supported by robust bootstrap values. In addition, strain PAMC28666 showed 77.08 and 23.3% ANI and DDH, respectively, with Glaciimonas sp. PCH181.This study focuses on how polar strain PAMC28666 responds to freeze-thaw conditions, Experimental results revealed a notable survival rate of 47.28% when subjected to a temperature of 15°C for a period of 10 days. Notably, two genes known to be responsive to cold stress, Trehalose 6-phosphate synthase (otsA) and Trehalose 6-phosphate phosphatase (otsB), exhibited increased expression levels as the temperature shifted from 25°C to 15°C. The upregulation of otsAB and the consequent synthesis of trehalose play pivotal roles in enhancing the cold resistance of strain PAMC28666, offering valuable insights into the correlation between trehalose production and adaptation to cold stress. Furthermore, research into this neglected cold-adapted variation, like Glaciimonas sp. PAMC28666, has the potential to shed light on how trehalose is produced in cold-adapted environments Additionally, there is potential to extract trehalose compounds from this strain for diverse biotechnological applications, including food and cosmetics, with ongoing research exploring its unique properties.

9.
Brief Bioinform ; 25(1)2023 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-37991247

RESUMO

The rapid growth of uncharacterized enzymes and their functional diversity urge accurate and trustworthy computational functional annotation tools. However, current state-of-the-art models lack trustworthiness on the prediction of the multilabel classification problem with thousands of classes. Here, we demonstrate that a novel evidential deep learning model (named ECPICK) makes trustworthy predictions of enzyme commission (EC) numbers with data-driven domain-relevant evidence, which results in significantly enhanced predictive power and the capability to discover potential new motif sites. ECPICK learns complex sequential patterns of amino acids and their hierarchical structures from 20 million enzyme data. ECPICK identifies significant amino acids that contribute to the prediction without multiple sequence alignment. Our intensive assessment showed not only outstanding enhancement of predictive performance on the largest databases of Uniprot, Protein Data Bank (PDB) and Kyoto Encyclopedia of Genes and Genomes (KEGG), but also a capability to discover new motif sites in microorganisms. ECPICK is a reliable EC number prediction tool to identify protein functions of an increasing number of uncharacterized enzymes.


Assuntos
Aprendizado Profundo , Proteínas/química , Bases de Dados de Proteínas , Genoma , Aminoácidos
11.
Int J Mol Sci ; 24(20)2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37894750

RESUMO

Cancer immunotherapy strategies are based on the utilization of immune checkpoint inhibitors to instigate an antitumor immune response. The efficacy of immune checkpoint blockade, directed at adaptive immune checkpoints, has been demonstrated in select cancer types. However, only a limited subset of patients has exhibited definitive outcomes characterized by a sustained response after discontinuation of therapy. Recent investigations have highlighted the significance of immune checkpoint molecules that are overexpressed in cancer cells and inhibit myeloid lineage immune cells within a tumor microenvironment. These checkpoints are identified as potential targets for anticancer immune responses. Notably, the immune checkpoint molecules CD24 and CD200 have garnered attention owing to their involvement in tumor immune evasion. CD24 and CD200 are overexpressed across diverse cancer types and serve as signaling checkpoints by engaging their respective receptors, Siglec-10 and CD200 receptor, which are expressed on tumor-associated myeloid cells. In this review, we summarized and discussed the latest advancements and insights into CD24 and CD200 as emergent immune checkpoint moieties, further delving into their therapeutic potentials for cancer treatment.


Assuntos
Proteínas de Checkpoint Imunológico , Neoplasias , Humanos , Antígeno CD24 , Imunoterapia , Células Mieloides , Neoplasias/patologia , Evasão Tumoral , Microambiente Tumoral
12.
Glycobiology ; 2023 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-37847605

RESUMO

Bacteria possess diverse metabolic and genetic processes, resulting in the inability of certain bacteria to degrade trehalose. However, some bacteria do have the capability to degrade trehalose, utilizing it as a carbon source, and for defense against environmental stress. Trehalose, a disaccharide, serves as a carbon source for many bacteria, including some that are vital for pathogens. The degradation of trehalose is carried out by enzymes like trehalase (EC 3.2.1.28) and trehalose phosphorylase (EC 2.4.1.64/2.4.1.231), which are classified under the glycoside hydrolase families GH37, GH15, and GH65. Numerous studies and reports have explored the physiological functions, recombinant expression, enzymatic characteristics, and potential applications of these enzymes. However, further research is still being conducted to understand their roles in bacteria. This review aims to provide a comprehensive summary of the current understanding of trehalose degradation pathways in various bacteria, focusing on three key areas: (i) identifying different trehalose-degrading enzymes in Gram-positive and Gram-negative bacteria, (ii) elucidating the mechanisms employed by trehalose-degrading enzymes belonging to the glycoside hydrolases GH37, GH15, and GH65, and (iii) discussing the potential applications of these enzymes in different sectors. Notably, this review emphasizes the bacterial trehalose-degrading enzymes, specifically trehalases (GH37, GH15, and GH65) and trehalose phosphorylases (GH65), in both Gram-positive and Gram-negative bacteria, an aspect that has not been highlighted before.

13.
Int J Biol Macromol ; 253(Pt 7): 127457, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37844821

RESUMO

The genomic analysis of Streptomyces sp. KCCM12257 presented 233 CAZyme genes with a predominant glycosyl hydrolase family. This contributes degradation of various polysaccharides including chitin and chitosan, and other promising candidates for the production of different oligosaccharides. We screened the strain providing different polysaccharides as a sole source of carbon and strain KCCM12257, showed higher activity towards colloidal chitosan. Further, we identified and characterized a new chitosanase (MDI5907146) of GH46 family. There was no activity towards chitin, carboxymethylcellulose, or even with chitosan powder. This enzyme acts on colloidal chitosan and hydrolyzes it down into monoacetyl chitobiose, which consists of two glucosamine units with an acetyl group attached to them. The maximum enzyme activity was observed at pH 6.5 and 40 °C using colloidal chitosan as a substrate. The Co2+ metal ions almost double the reaction as compared to other metal ions. The dissociation constant (Km) and of colloidal chitosan (≥90 % and ≥75%DD) were 3.03 mg/ml and 5.01 mg/ml respectively, while maximum velocity (Vmax) values were found to be 36 mg/ml, and 30 µM/µg/min, respectively. Similarly, catalytic efficiency (Kcat/Km) of colloidal chitosan with ≥90 %DD was 1.9 fold higher than colloidal chitosan with ≥75%DD.


Assuntos
Quitosana , Streptomyces , Quitosana/química , Glicosídeo Hidrolases/química , Quitina/química , Polissacarídeos , Íons
14.
Sci Rep ; 13(1): 17854, 2023 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-37857791

RESUMO

Heavy metals, including mercury, are non-biodegradable and highly toxic to microorganisms even at low concentrations. Understanding the mechanisms underlying the environmental adaptability of microorganisms with Hg resistance holds promise for their use in Hg bioremediation. We characterized GbsMerA, a mercury reductase belonging to the mercury-resistant operon of Gelidibacter salicanalis PAMC21136, and found its maximum activity of 474.7 µmol/min/mg in reducing Hg+2. In the presence of Ag and Mn, the enzyme exhibited moderate activity as 236.5 µmol/min/mg and 69 µmol/min/mg, respectively. GbsMerA exhibited optimal activity at pH 7.0 and a temperature of 60 °C. Moreover, the crystal structure of GbsMerA and structural comparison with homologues indicated that GbsMerA contains residues, Tyr437´ and Asp47, which may be responsible for metal transfer at the si-face by providing a hydroxyl group (-OH) to abstract a proton from the thiol group of cysteine. The complex structure with NADPH indicated that Y174 in the re-face can change its side chain direction upon NADPH binding, indicating that Y174 may have a role as a gate for NADPH binding. Moreover, the heterologous host expressing GbsMerA (pGbsMerA) is more resistant to Hg toxicity when compared to the host lacking GbsMerA. Overall, this study provides a background for understanding the catalytic mechanism and Hg detoxification by GbsMerA and suggests the application of genetically engineered E. coli strains for environmental Hg removal.


Assuntos
Escherichia coli , Mercúrio , Escherichia coli/metabolismo , NADP , Mercúrio/metabolismo , Oxirredutases/genética , Oxirredutases/metabolismo
15.
Biomater Res ; 27(1): 83, 2023 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-37660070

RESUMO

BACKGROUND: Despite the effectiveness of glucagon-like peptide-1 agonist (GLP-1A) in the treatment of diabetes, its large molecular weight and high hydrophilicity result in poor cellular permeability, thus limiting its oral bioavailability. To address this, we developed a chimeric GLP-1A that targets transporter-mediated endocytosis to enhance cellular permeability to GLP-1A by utilizing the transporters available in the intestine, particularly the apical sodium-dependent bile acid transporter (ASBT). METHODS: In silico molecular docking and molecular dynamics simulations were used to investigate the binding interactions of mono-, bis-, and tetra-deoxycholic acid (DOCA) (monoDOCA, bisDOCA, and tetraDOCA) with ASBT. After synthesizing the chimeric GLP-1A-conjugated oligomeric DOCAs (mD-G1A, bD-G1A, and tD-G1A) using a maleimide reaction, in vitro cellular permeability and insulinotropic effects were assessed. Furthermore, in vivo oral absorption in rats and hypoglycemic effect on diabetic db/db mice model were evaluated. RESULTS: In silico results showed that tetraDOCA had the lowest interaction energy, indicating high binding affinity to ASBT. Insulinotropic effects of GLP-1A-conjugated oligomeric DOCAs were not different from those of GLP-1A-Cys or exenatide. Moreover, bD-G1A and tD-G1A exhibited improved in vitro Caco-2 cellular permeability and showed higher in vivo bioavailability (7.58% and 8.63%) after oral administration. Regarding hypoglycemic effects on db/db mice, tD-G1A (50 µg/kg) lowered the glucose level more than bD-G1A (50 µg/kg) compared with the control (35.5% vs. 26.4%). CONCLUSION: GLP-1A was conjugated with oligomeric DOCAs, and the resulting chimeric compound showed the potential not only for glucagon-like peptide-1 receptor agonist activity but also for oral delivery. These findings suggest that oligomeric DOCAs can be used as effective carriers for oral delivery of GLP-1A, offering a promising solution for enhancing its oral bioavailability and improving diabetes treatment.

16.
17.
Protein Expr Purif ; 212: 106352, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37595854

RESUMO

Insolubility and low expression are typical bottlenecks in the production of proteins for studying their function and structure using X-ray crystallography or nuclear magnetic resonance spectroscopy. Cold-active enzymes from polar microorganisms have unique structural features that render them unstable and thermolabile, and are responsible for decreased protein yield in heterologous expression systems. To address these challenges, we developed a heterologous protein expression system using a psychrophilic organism, Psychrobacter sp. PAMC 21119, as a protein expression host with its own promoter. We screened 11 promoters and evaluated their strength using quantitative real-time polymerase chain reaction and a reporter system harboring the SfGFP gene. The highest expression was achieved using promoters RH96_RS13655 (P21119_20930) and RH96_RS15090 (P21119_23410), regardless of the temperature used. The p20930 strain exhibited a maximum expression level 19.6-fold higher than that of its control at 20 °C and produced approximately 0.5 mg of protein per gram of dry cell weight. To our knowledge, this is the first report of a low-temperature recombinant protein expression system developed using Psychrobacter sp. that can be used to express various difficult-to-express and cold-active proteins.


Assuntos
Psychrobacter , Proteínas de Fluorescência Verde/genética , Psychrobacter/genética , Temperatura Baixa , Cristalografia por Raios X , Regiões Promotoras Genéticas
18.
Sci Rep ; 13(1): 13243, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37582969

RESUMO

A great diversity of crustacean zooplankton found in inland and coastal waters produce embryos that settle into bottom sediments to form an egg bank. Embryos from these banks can remain dormant for centuries, creating a reservoir of genetic diversity. A large body of literature describes the ecological and evolutionary importance of zooplankton egg banks. However, literature on the physiological traits behind dormancy in crustacean zooplankton are limited. Most data on the physiology of dormancy comes from research on one species of anostracan, the brine shrimp, Artemia franciscana. Anoxia-induced dormancy in this species is facilitated by a profound and reversible acidification of the intracellular space. This acidification is accompanied by a reversible depletion of adenosine triphosphate (ATP). The present study demonstrates that acidification of the intracellular space also occurs in concert with a depletion of nucleoside triphosphates (NTPs) in the Antarctic copepod, Boeckella poppei. Like A. franciscana, the depletion of NTPs and acidification are rapidly reversed during aerobic recovery in B. poppei. These data provide the first comparative evidence that extreme dormancy under anoxia in crustacean zooplankton is associated with intracellular acidification and an ability to recover from the depletion of ATP.


Assuntos
Copépodes , Animais , Regiões Antárticas , Hipóxia , Água Doce , Trifosfato de Adenosina , Concentração de Íons de Hidrogênio , Artemia/fisiologia
19.
Int J Mol Sci ; 24(15)2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37569396

RESUMO

This study aimed to elucidate the crystal structure and biochemically characterize the carboxylesterase EaEst2, a thermotolerant biocatalyst derived from Exiguobacterium antarcticum, a psychrotrophic bacterium. Sequence and phylogenetic analyses showed that EaEst2 belongs to the Family XIII group of carboxylesterases. EaEst2 has a broad range of substrate specificities for short-chain p-nitrophenyl (pNP) esters, 1-naphthyl acetate (1-NA), and 1-naphthyl butyrate (1-NB). Its optimal pH is 7.0, losing its enzymatic activity at temperatures above 50 °C. EaEst2 showed degradation activity toward bis(2-hydroxyethyl) terephthalate (BHET), a polyethylene terephthalate degradation intermediate. We determined the crystal structure of EaEst2 at a 1.74 Å resolution in the ligand-free form to investigate BHET degradation at a molecular level. Finally, the biochemical stability and immobilization of a crosslinked enzyme aggregate (CLEA) were assessed to examine its potential for industrial application. Overall, the structural and biochemical characterization of EaEst2 demonstrates its industrial potency as a biocatalyst.


Assuntos
Bacillaceae , Carboxilesterase , Carboxilesterase/genética , Filogenia , Bacillaceae/metabolismo , Hidrolases de Éster Carboxílico/metabolismo , Especificidade por Substrato
20.
Microorganisms ; 11(7)2023 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-37512929

RESUMO

The members of Microbacterium isolated from different environments are known to form peptidoglycan. In this study, we compared the biofilm-forming abilities of Microbacterium sp. PAMC22086 (PAMC22086), which was isolated from the soil in the South Shetland Islands and Microbacterium sp. PAMC21962 (PAMC21962), which was isolated from algae in the South Shetland Islands. The analysis of average nucleotide identity and phylogeny of PAMC22086 revealed a 97% similarity to Microbacterium oxydans VIU2A, while PAMC21962 showed a 99.1% similarity to Microbacterium hominis SGAir0570. For the comparative genomic analysis of PAMC22086 and PAMC21962, the genes related to biofilm formation were identified using EggNOG and KEGG pathway databases. The genes possessed by both PAMC22086 and PAMC21962 are cpdA, phnB, rhlC, and glgC, which regulate virulence, biofilm formation, and multicellular structure. Among the genes indirectly involved in biofilm formation, unlike PAMC21962, PAMC22086 possessed csrA, glgC, and glgB, which are responsible for attachment and glycogen biosynthesis. Additionally, in PAMC22086, additional functional genes rsmA, which is involved in mobility and polysaccharide production, and dksA, GTPase, and oxyR, which play roles in cell cycle and stress response, were identified. In addition, the biofilm-forming ability of the two isolates was examined in vivo using the standard crystal violet staining technique, and morphological differences in the biofilm were investigated. It is evident from the different distribution of biofilm-associated genes between the two strains that the bacteria can survive in different niches by employing distinct strategies. Both strains exhibit distinct morphologies. PAMC22086 forms a biofilm that attaches to the side, while PAMC21962 indicates growth starting from the center. The biofilm formation-related genes in Microbacterium are not well understood. However, it has been observed that Microbacterium species form biofilm regardless of the number of genes they possess. Through comparison between different Microbacterium species, it was revealed that specific core genes are involved in cell adhesion, which plays a crucial role in biofilm formation. This study provides a comprehensive profile of the Microbacterium genus's genomic features and a preliminary understanding of biofilm in this genus, laying the foundation for further research.

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