Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Cell Rep ; 42(7): 112756, 2023 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-37418323

RESUMO

Bacterial cell-wall hydrolases must be tightly regulated during bacterial cell division to prevent aberrant cell lysis and to allow final separation of viable daughter cells. In a multidisciplinary work, we disclose the molecular dialogue between the cell-wall hydrolase LytB, wall teichoic acids, and the eukaryotic-like protein kinase StkP in Streptococcus pneumoniae. After characterizing the peptidoglycan recognition mode by the catalytic domain of LytB, we further demonstrate that LytB possesses a modular organization allowing the specific binding to wall teichoic acids and to the protein kinase StkP. Structural and cellular studies notably reveal that the temporal and spatial localization of LytB is governed by the interaction between specific modules of LytB and the final PASTA domain of StkP. Our data collectively provide a comprehensive understanding of how LytB performs final separation of daughter cells and highlights the regulatory role of eukaryotic-like kinases on lytic machineries in the last step of cell division in streptococci.


Assuntos
Proteínas Serina-Treonina Quinases , Streptococcus pneumoniae , Streptococcus pneumoniae/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Ácidos Teicoicos/metabolismo , Proteínas de Bactérias/metabolismo , Divisão Celular , Proteínas Quinases/metabolismo , Hidrolases/metabolismo , Parede Celular/metabolismo
2.
Free Radic Biol Med ; 204: 215-225, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37156295

RESUMO

KEAP1 promotes the ubiquitin-dependent degradation of NRF2 by assembling into a CUL3-dependent ubiquitin ligase complex. Oxidative and electrophilic stress inhibit KEAP1 allowing NRF2 to accumulate for the transactivation of stress response genes. To date there are no structures of the KEAP1-CUL3 interaction nor binding data to show the contributions of different domains to their binding affinity. We determined a crystal structure of the BTB and 3-box domains of human KEAP1 in complex with the CUL3 N-terminal domain that showed a heterotetrameric assembly with 2:2 stoichiometry. To support the structural data, we developed a versatile TR-FRET-based assay system to profile the binding of BTB-domain-containing proteins to CUL3 and determine the contribution of distinct protein features, revealing the importance of the CUL3 N-terminal extension for high affinity binding. We further provide direct evidence that the investigational drug CDDO does not disrupt the KEAP1-CUL3 interaction, even at high concentrations, but reduces the affinity of KEAP1-CUL3 binding. The TR-FRET-based assay system offers a generalizable platform for profiling this protein class and may form a suitable screening platform for ligands that disrupt these interactions by targeting the BTB or 3-box domains to block E3 ligase function.


Assuntos
Proteínas Culina , Fator 2 Relacionado a NF-E2 , Humanos , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Proteínas Culina/genética , Proteínas Culina/metabolismo , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Ligação Proteica
3.
Proc Natl Acad Sci U S A ; 118(39)2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34544876

RESUMO

Aspergillus fumigatus is a human opportunistic pathogen showing emerging resistance against a limited repertoire of antifungal agents available. The GTPase Rho1 has been identified as an important regulator of the cell wall integrity signaling pathway that regulates the composition of the cell wall, a structure that is unique to fungi and serves as a target for antifungal compounds. Rom2, the guanine nucleotide exchange factor to Rho1, contains a C-terminal citron homology (CNH) domain of unknown function that is found in many other eukaryotic genes. Here, we show that the Rom2 CNH domain interacts directly with Rho1 to modulate ß-glucan and chitin synthesis. We report the structure of the Rom2 CNH domain, revealing that it adopts a seven-bladed ß-propeller fold containing three unusual loops. A model of the Rho1-Rom2 CNH complex suggests that the Rom2 CNH domain interacts with the Rho1 Switch II motif. This work uncovers the role of the Rom2 CNH domain as a scaffold for Rho1 signaling in fungal cell wall biosynthesis.


Assuntos
Aspergillus fumigatus/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Parede Celular/fisiologia , Proteínas Fúngicas/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas rho de Ligação ao GTP/metabolismo , Aspergillus fumigatus/genética , Aspergillus fumigatus/crescimento & desenvolvimento , Fatores de Transcrição de Zíper de Leucina Básica/química , Fatores de Transcrição de Zíper de Leucina Básica/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Peptídeos e Proteínas de Sinalização Intracelular/química , Peptídeos e Proteínas de Sinalização Intracelular/genética , Conformação Proteica , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/genética , Transdução de Sinais , Proteínas rho de Ligação ao GTP/química , Proteínas rho de Ligação ao GTP/genética
4.
FEBS Lett ; 594(4): 717-727, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31627256

RESUMO

X-linked intellectual disabilities (XLID) are common developmental disorders. The enzyme O-GlcNAc transferase encoded by OGT, a recently discovered XLID gene, attaches O-GlcNAc to nuclear and cytoplasmic proteins. As few missense mutations have been described, it is unclear what the aetiology of the patient phenotypes is. Here, we report the discovery of a missense mutation in the catalytic domain of OGT in an XLID patient. X-ray crystallography reveals that this variant leads to structural rearrangements in the catalytic domain. The mutation reduces in vitro OGT activity on substrate peptides/protein. Mouse embryonic stem cells carrying the mutation reveal reduced O-GlcNAcase (OGA) and global O-GlcNAc levels. These data suggest a direct link between changes in the O-GlcNAcome and intellectual disability observed in patients carrying OGT mutations.


Assuntos
Domínio Catalítico , Deficiência Intelectual/enzimologia , Deficiência Intelectual/genética , Mutação de Sentido Incorreto , N-Acetilglucosaminiltransferases/química , N-Acetilglucosaminiltransferases/genética , Animais , Linhagem Celular , Glicosilação , Humanos , Deficiência Intelectual/metabolismo , Camundongos , Modelos Moleculares , N-Acetilglucosaminiltransferases/metabolismo
5.
Mol Microbiol ; 108(2): 128-142, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29405497

RESUMO

Endolysins are bacteriophage-encoded peptidoglycan hydrolases that specifically degrade the bacterial cell wall at the end of the phage lytic cycle. They feature a distinct modular architecture, consisting of enzymatically active domains (EADs) and cell wall-binding domains (CBDs). Structural analysis of the complete enzymes or individual domains is required for better understanding the mechanisms of peptidoglycan degradation and provides guidelines for the rational design of chimeric enzymes. We here report the crystal structure of the EAD of PlyP40, a member of the GH-25 family of glycosyl hydrolases, and the first muramidase reported for Listeria phages. Site-directed mutagenesis confirmed key amino acids (Glu98 and Trp10) involved in catalysis and substrate stabilization. In addition, we found that PlyP40 contains two heterogeneous CBD modules with homology to SH3 and LysM domains. Truncation analysis revealed that both domains are required for full activity but contribute to cell wall recognition and lysis differently. Replacement of CBDP40 with a corresponding domain from a different Listeria phage endolysin yielded an enzyme with a significant shift in pH optimum. Finally, domain swapping between PlyP40 and the streptococcal endolysin Cpl-1 produced an intergeneric chimera with activity against Listeria cells, indicating that structural similarity of individual domains determines enzyme function.


Assuntos
Bacteriófagos/enzimologia , Listeria monocytogenes/virologia , N-Acetil-Muramil-L-Alanina Amidase/química , N-Acetil-Muramil-L-Alanina Amidase/metabolismo , Proteínas Virais/química , Proteínas Virais/metabolismo , Motivos de Aminoácidos , Bacteriófagos/química , Bacteriófagos/genética , Catálise , Domínio Catalítico , Parede Celular/metabolismo , Parede Celular/virologia , Concentração de Íons de Hidrogênio , Listeria monocytogenes/metabolismo , N-Acetil-Muramil-L-Alanina Amidase/genética , Peptidoglicano/metabolismo , Ligação Proteica , Proteínas Virais/genética
6.
Int J Med Microbiol ; 308(6): 692-704, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29100886

RESUMO

Bacterial lipoproteins (Lpp) compose a large family of surface-exposed proteins that are involved in diverse, but critical, cellular functions spanning from fitness to virulence. All of them present a common signature, a sequence motif, known as LipoBox, containing an invariant Cys residue that allows the protein to be covalently bound to the membrane through a thioether linkage. Despite the abundance and relevance of Lpp, there is a scarcity of structural and functional information for this family of proteins. In this review, the updated structural and functional data for Lpp from two Gram-positive pathogenic model organisms, Staphylococcus aureus and Streptococcus pneumoniae is presented. The available structural information offers a glimpse over the Lpp functional mechanisms. Their relevance in bacterial fitness, and also in virulence and host-pathogen interactions, reveals lipoproteins as very attractive targets for designing of novel antimicrobials, and interesting candidates as novel vaccine antigens.


Assuntos
Proteínas de Bactérias/química , Lipoproteínas/química , Staphylococcus aureus/química , Staphylococcus aureus/patogenicidade , Streptococcus pneumoniae/química , Streptococcus pneumoniae/patogenicidade , Interações Hospedeiro-Patógeno , Proteínas de Membrana/química , Estrutura Terciária de Proteína , Virulência
7.
ACS Med Chem Lett ; 8(3): 327-332, 2017 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-28337325

RESUMO

Acute lung injury (ALI) is a deadly symptom for serious lung inflammation. Discoidin Domain Receptor 1 (DDR1) is a new potential target for anti-inflammatory drug discovery. A new selective tetrahydroisoquinoline-7-carboxamide based DDR1 inhibitor 7ae was discovered to tightly bind the DDR1 protein and potently inhibit its kinase function with a Kd value of 2.2 nM and an IC50 value of 6.6 nM, respectively. The compound dose-dependently inhibited lipopolysaccharide (LPS)-induced interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) release in mouse primary peritoneal macrophages (MPMs). In addition, 7ae also exhibited promising in vivo anti-inflammatory effects in a LPS-induced mouse ALI model. To the best of our knowledge, this is the first "proof of concept" investigation on the potential application of a small molecule DDR1 inhibitor to treat ALI.

8.
J Med Chem ; 59(12): 5911-6, 2016 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-27219676

RESUMO

The structure-based design of 1, 2, 3, 4-tetrahydroisoquinoline derivatives as selective DDR1 inhibitors is reported. One of the representative compounds, 6j, binds to DDR1 with a Kd value of 4.7 nM and suppresses its kinase activity with an IC50 value of 9.4 nM, but it is significantly less potent for a panel of 400 nonmutated kinases. 6j also demonstrated reasonable pharmacokinetic properties and a promising oral therapeutic effect in a bleomycin-induced mouse pulmonary fibrosis model.


Assuntos
Receptor com Domínio Discoidina 1/antagonistas & inibidores , Desenho de Fármacos , Isoquinolinas/farmacologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Fibrose Pulmonar/tratamento farmacológico , Administração Oral , Animais , Bleomicina , Receptor com Domínio Discoidina 1/metabolismo , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Isoquinolinas/administração & dosagem , Isoquinolinas/química , Camundongos , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/uso terapêutico , Fibrose Pulmonar/induzido quimicamente , Relação Estrutura-Atividade
9.
Structure ; 22(11): 1595-606, 2014 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-25450767

RESUMO

SIGN-R1 is a principal receptor for microbial polysaccharides uptake and is responsible for C3 fixation via an unusual complement activation pathway on splenic marginal zone macrophages. In these macrophages, SIGN-R1 is also involved in anti-inflammatory activity of intravenous immunoglobulin by direct interaction with sialylated Fcs. The high-resolution crystal structures of SIGN-R1 carbohydrate recognition domain and its complexes with dextran sulfate or sialic acid, and of the sialylated Fc antibody provide insights into SIGN-R1's selective recognition of a-2,6-sialylated glycoproteins. Unexpectedly, an additional binding site has been found in the SIGNR1 carbohydrate recognition domain, structurally separate from the calcium-dependent carbohydrate-binding site. This secondary binding site could bind repetitive molecular patterns, as observed in microbial polysaccharides, in a calcium-independent manner. These two binding sites may allow SIGNR1 to simultaneously bind both immune glycoproteins and microbial polysaccharide components, accommodating SIGN-R1's ability to relate the recognition of microbes to the activation of the classical complement pathway.


Assuntos
Moléculas de Adesão Celular/química , Moléculas de Adesão Celular/metabolismo , Sulfato de Dextrana/metabolismo , Fragmentos Fc das Imunoglobulinas/metabolismo , Lectinas Tipo C/química , Lectinas Tipo C/metabolismo , Ácido N-Acetilneuramínico/metabolismo , Receptores de Superfície Celular/química , Receptores de Superfície Celular/metabolismo , Animais , Sítios de Ligação , Células CHO , Cricetulus , Cristalografia por Raios X , Humanos , Camundongos , Modelos Moleculares , Estrutura Secundária de Proteína
10.
ACS Chem Biol ; 9(9): 2058-66, 2014 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-24988330

RESUMO

The lytic transglycosylases are essential bacterial enzymes that catalyze the nonhydrolytic cleavage of the glycan strands of the bacterial cell wall. We describe here the structural and catalytic properties of MltC, one of the seven lytic transglycosylases found in the genome of the Gram-negative bacterium Escherichia coli. The 2.3 Å resolution X-ray structure of a soluble construct of MltC shows a unique, compared to known lytic transglycosylase structures, two-domain structure characterized by an expansive active site of 53 Å length extending through an interface between the domains. The structures of three complexes of MltC with cell wall analogues suggest the positioning of the peptidoglycan in the active site both as a substrate and as a product. One complex is suggested to correspond to an intermediate in the course of sequential and exolytic cleavage of the peptidoglycan. Moreover, MltC partitioned its reactive oxocarbenium-like intermediate between trapping by the C6-hydroxyl of the muramyl moiety (lytic transglycosylase activity, the major path) and by water (muramidase activity). Genomic analysis identifies the presence of an MltC homologue in no less than 791 bacterial genomes. While the role of MltC in cell wall assembly and maturation remains uncertain, we propose a functional role for this enzyme as befits the uniqueness of its two-domain structure.


Assuntos
Proteínas de Escherichia coli/metabolismo , Glicosiltransferases/química , Glicosiltransferases/metabolismo , Domínio Catalítico , Parede Celular/metabolismo , Clonagem Molecular , Cristalografia por Raios X , Escherichia coli/citologia , Escherichia coli/metabolismo , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Modelos Moleculares , Mutação , Peptidoglicano/química , Conformação Proteica , Estrutura Terciária de Proteína
11.
Nat Commun ; 5: 3842, 2014 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-24804636

RESUMO

Separation of daughter cells during bacterial cell division requires splitting of the septal cross wall by peptidoglycan hydrolases. In Streptococcus pneumoniae, PcsB is predicted to perform this operation. Recent evidence shows that PcsB is recruited to the septum by the transmembrane FtsEX complex, and that this complex is required for cell division. However, PcsB lacks detectable catalytic activity in vitro, and while it has been proposed that FtsEX activates PcsB, evidence for this is lacking. Here we demonstrate that PcsB has muralytic activity, and report the crystal structure of full-length PcsB. The protein adopts a dimeric structure in which the V-shaped coiled-coil (CC) domain of each monomer acts as a pair of molecular tweezers locking the catalytic domain of each dimeric partner in an inactive configuration. This suggests that the release of the catalytic domains likely requires an ATP-driven conformational change in the FtsEX complex, conveyed towards the catalytic domains through coordinated movements of the CC domain.


Assuntos
Proteínas de Bactérias/metabolismo , Divisão Celular/fisiologia , N-Acetil-Muramil-L-Alanina Amidase/metabolismo , Streptococcus pneumoniae/fisiologia , Proteínas de Bactérias/ultraestrutura , Domínio Catalítico/fisiologia , Divisão Celular/genética , Parede Celular/fisiologia , Cristalografia por Raios X , Streptococcus pneumoniae/genética
12.
Biochim Biophys Acta ; 1840(1): 129-35, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24036328

RESUMO

BACKGROUND: Streptococcus pneumoniae is a major pathogen responsible of important diseases worldwide such as pneumonia and meningitis. An increasing resistance level hampers the use of currently available antibiotics to treat pneumococcal diseases. Consequently, it is desirable to find new targets for the development of novel antimicrobial drugs to treat pneumococcal infections. Surface choline-binding proteins (CBPs) are essential in bacterial physiology and infectivity. In this sense, esters of bicyclic amines (EBAs) such as atropine and ipratropium have been previously described to act as choline analogs and effectively compete with teichoic acids on binding to CBPs, consequently preventing in vitro pneumococcal growth, altering cell morphology and reducing cell viability. METHODS: With the aim of gaining a deeper insight into the structural determinants of the strong interaction between CBPs and EBAs, the three-dimensional structures of choline-binding protein F (CbpF), one of the most abundant proteins in the pneumococcal cell wall, complexed with atropine and ipratropium, have been obtained. RESULTS: The choline analogs bound both to the carboxy-terminal module, involved in cell wall binding, and, unexpectedly, also to the amino-terminal module, that possesses a regulatory role in pneumococcal autolysis. CONCLUSIONS: Analysis of the complexes confirmed the importance of the tropic acid moiety of the EBAs on the strength of the binding, through π-π interactions with aromatic residues in the binding site. GENERAL SIGNIFICANCE: These results represent the first example describing the molecular basis of the inhibition of CBPs by EBA molecules and pave the way for the development of new generations of antipneumococcal drugs.


Assuntos
Atropina/metabolismo , Colina/metabolismo , Desenho de Fármacos , Ipratrópio/metabolismo , Receptores de Superfície Celular/química , Streptococcus pneumoniae/metabolismo , Sítios de Ligação , Cristalização , Cristalografia por Raios X , Modelos Moleculares , Conformação Proteica , Receptores de Superfície Celular/metabolismo
13.
EMBO Mol Med ; 5(12): 1852-70, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24136784

RESUMO

The respiratory pathogen Streptococcus pneumoniae has evolved efficient mechanisms to resist oxidative stress conditions and to displace other bacteria in the nasopharynx. Here we characterize at physiological, functional and structural levels two novel surface-exposed thioredoxin-family lipoproteins, Etrx1 and Etrx2. The impact of both Etrx proteins and their redox partner methionine sulfoxide reductase SpMsrAB2 on pneumococcal pathogenesis was assessed in mouse virulence studies and phagocytosis assays. The results demonstrate that loss of function of either both Etrx proteins or SpMsrAB2 dramatically attenuated pneumococcal virulence in the acute mouse pneumonia model and that Etrx proteins compensate each other. The deficiency of Etrx proteins or SpMsrAB2 further enhanced bacterial uptake by macrophages, and accelerated pneumococcal killing by H2 O2 or free methionine sulfoxides (MetSO). Moreover, the absence of both Etrx redox pathways provokes an accumulation of oxidized SpMsrAB2 in vivo. Taken together our results reveal insights into the role of two extracellular electron pathways required for reduction of SpMsrAB2 and surface-exposed MetSO. Identification of this system and its target proteins paves the way for the design of novel antimicrobials.


Assuntos
Proteínas de Bactérias/metabolismo , Streptococcus pneumoniae/metabolismo , Animais , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Domínio Catalítico , Cristalografia por Raios X , Modelos Animais de Doenças , Feminino , Peróxido de Hidrogênio/farmacologia , Macrófagos/imunologia , Macrófagos/fisiologia , Metionina/análogos & derivados , Metionina/farmacologia , Camundongos , Dados de Sequência Molecular , Estresse Oxidativo/efeitos dos fármacos , Fagocitose , Pneumonia/imunologia , Pneumonia/microbiologia , Pneumonia/mortalidade , Estrutura Terciária de Proteína , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Streptococcus pneumoniae/patogenicidade , Análise de Sobrevida , Virulência
14.
Acta Crystallogr Sect F Struct Biol Cryst Commun ; 67(Pt 10): 1285-9, 2011 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22102049

RESUMO

Phosphoglycerate kinase (PGK) is a widespread two-domain enzyme that plays a critical role in the glycolytic pathway. Several glycolytic enzymes from streptococci have been identified as surface-exposed proteins that are involved in streptococcal virulence by their ability to bind host proteins. This binding allows pneumococcal cells to disseminate through the epithelial and endothelial layers. Crystallization of PGK from Streptococcus pneumoniae yielded orthorhombic crystals (space group I222, unit-cell parameters a = 62.73, b = 75.38, c = 83.63 Å). However, the unit cell of these crystals was not compatible with the presence of full-length PGK. Various analytical methods showed that only the N-terminal domain of PGK was present in the I222 crystals. The ternary complex of PGK with adenylyl imidodiphosphate (AMP-PNP) and 3-phospho-D-glycerate (3PGA) produced monoclinic crystals (space group P2(1), unit-cell parameters a = 40.35, b = 78.23, c = 59.03 Å, ß = 96.34°). Molecular replacement showed that this new crystal form contained full-length PGK, thereby indicating the relevance of including substrates in order to avoid proteolysis during the crystallization process.


Assuntos
Fosfoglicerato Quinase/química , Streptococcus pneumoniae/enzimologia , Cristalização , Cristalografia por Raios X
15.
Proteins ; 79 Suppl 10: 6-20, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22020785

RESUMO

One goal of the CASP community wide experiment on the critical assessment of techniques for protein structure prediction is to identify the current state of the art in protein structure prediction and modeling. A fundamental principle of CASP is blind prediction on a set of relevant protein targets, that is, the participating computational methods are tested on a common set of experimental target proteins, for which the experimental structures are not known at the time of modeling. Therefore, the CASP experiment would not have been possible without broad support of the experimental protein structural biology community. In this article, several experimental groups discuss the structures of the proteins which they provided as prediction targets for CASP9, highlighting structural and functional peculiarities of these structures: the long tail fiber protein gp37 from bacteriophage T4, the cyclic GMP-dependent protein kinase Iß dimerization/docking domain, the ectodomain of the JTB (jumping translocation breakpoint) transmembrane receptor, Autotaxin in complex with an inhibitor, the DNA-binding J-binding protein 1 domain essential for biosynthesis and maintenance of DNA base-J (ß-D-glucosyl-hydroxymethyluracil) in Trypanosoma and Leishmania, an so far uncharacterized 73 residue domain from Ruminococcus gnavus with a fold typical for PDZ-like domains, a domain from the phycobilisome core-membrane linker phycobiliprotein ApcE from Synechocystis, the heat shock protein 90 activators PFC0360w and PFC0270w from Plasmodium falciparum, and 2-oxo-3-deoxygalactonate kinase from Klebsiella pneumoniae.


Assuntos
Biologia Computacional/métodos , Modelos Moleculares , Proteínas/química , Sequência de Aminoácidos , Animais , Bacteriófago T4/química , Proteínas Quinases Dependentes de GMP Cíclico/química , Proteínas de Ligação a DNA/química , Humanos , Klebsiella pneumoniae/química , Klebsiella pneumoniae/enzimologia , Leishmania/química , Dados de Sequência Molecular , Diester Fosfórico Hidrolases/química , Fosfotransferases (Aceptor do Grupo Álcool)/química , Plasmodium falciparum/química , Conformação Proteica , Dobramento de Proteína , Proteínas de Protozoários/química , Trypanosoma/química , Proteínas Virais/química
16.
Proc Natl Acad Sci U S A ; 107(47): 20287-92, 2010 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-21041684

RESUMO

Bacteriophages are the most numerous organisms in the biosphere. In spite of their biological significance and the spectrum of potential applications, little high-resolution structural detail is available on their receptor-binding fibers. Here we present the crystal structure of the receptor-binding tip of the bacteriophage T4 long tail fiber, which is highly homologous to the tip of the bacteriophage lambda side tail fibers. This structure reveals an unusual elongated six-stranded antiparallel beta-strand needle domain containing seven iron ions coordinated by histidine residues arranged colinearly along the core of the biological unit. At the end of the tip, the three chains intertwine forming a broader head domain, which contains the putative receptor interaction site. The structure reveals a previously unknown beta-structured fibrous fold, provides insights into the remarkable stability of the fiber, and suggests a framework for mutations to expand or modulate receptor-binding specificity.


Assuntos
Bacteriófago T4/genética , Modelos Moleculares , Conformação Proteica , Proteínas da Cauda Viral/química , Sequência de Aminoácidos , Cristalografia por Raios X , Dados de Sequência Molecular , Dobramento de Proteína , Estabilidade Proteica , Alinhamento de Sequência , Espectrometria por Raios X , Proteínas da Cauda Viral/genética
17.
J Clin Microbiol ; 43(9): 4382-90, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16145081

RESUMO

In this study a multilocus sequence typing (MLST) scheme for Acinetobacter baumannii was developed and evaluated by using 40 clinical A. baumannii isolates recovered from outbreaks in Spanish and German hospitals during the years 1990 to 2001, as well as isolates from other European hospitals and two DSMZ reference strains of A. baumannii. For comparison, two isolates of Acinetobacter species 13 (sensu Tjernberg and Ursing), two clinical isolates, and three DSMZ strains of A. calcoaceticus (both belonging to the A. calcoaceticus-A. baumannii complex) were also investigated. Primers were designed for conserved regions of housekeeping genes, and 305- to 513-bp internal fragments of seven such genes-gltA, gyrB, gdhB, recA, cpn60, gpi, and rpoD-were sequenced for all strains. The number of alleles at individual loci ranged from 6 to 12, and a total of 20 allelic profiles or sequence types were distinguished among the investigated A. baumannii strains. The MLST data were in high concordance with the epidemiologic typing results generated by pulsed-field gel electrophoresis and amplified fragment length polymorphism fingerprinting. The MLST scheme provides a high level of resolution and an excellent tool for studying the population structure and long-term epidemiology of A. baumannii.


Assuntos
Infecções por Acinetobacter/epidemiologia , Acinetobacter baumannii/classificação , Acinetobacter baumannii/genética , Alelos , Proteínas de Bactérias/genética , Técnicas de Tipagem Bacteriana , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/isolamento & purificação , Primers do DNA , Eletroforese em Gel de Campo Pulsado , Humanos , Epidemiologia Molecular , Dados de Sequência Molecular , Análise de Sequência de DNA
18.
Environ Microbiol ; 7(5): 649-59, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15819847

RESUMO

The genetic diversity of 19 strains belonging to Alteromonas macleodii isolated from different geographic areas (Pacific and Indian Ocean, and different parts of the Mediterranean Sea) and at different depths (from the surface down to 3500 m) has been studied. Fragments of the 16S rRNA gene, the internal transcribed spacer (ITS) between 16S and 23S rDNA genes, the gyrB and the rpoB genes, have been sequenced for each strain. Amplified fragment length polymorphisms were used to characterize similarity at the level of the whole genome. Most of the diversity reflected the existence of a cluster of strains isolated from deep Mediterranean waters and two isolates from the Black Sea. Particularly the isolates from the deep sites were consistently different from all the others indicating the existence of a specific ecotype adapted to these conditions. Amplification of gyrB gene and ITS directly from DNA retrieved from deep Mediterreanean waters and one Atlantic sample showed that presence of this deep-sea ecotype is widespread and is not a product of culture bias. On the other hand, strains isolated from surface tropical waters showed a remarkable level of resemblance to the first isolate of this species obtained from Hawaii in 1972. The results indicate the existence of both lineages of global distribution and ecotypes adapted to specific conditions such as deep or more diluted (the Black Sea) waters.


Assuntos
Alteromonas/genética , DNA Girase/genética , RNA Polimerases Dirigidas por DNA/genética , RNA Ribossômico 16S/genética , Alteromonas/enzimologia , Sequência de Bases , Impressões Digitais de DNA , DNA Girase/química , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , RNA Polimerases Dirigidas por DNA/química , Genes Bacterianos , Variação Genética , Mar Mediterrâneo , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Polimorfismo Genético , RNA Ribossômico 16S/química , Alinhamento de Sequência
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...