scholarly journals Streptococcal phosphotransferase system imports unsaturated hyaluronan disaccharide derived from host extracellular matrices

2018 ◽  
Author(s):  
Sayoko Oiki ◽  
Yusuke Nakamichi ◽  
Yukie Maruyama ◽  
Bunzo Mikami ◽  
Kousaku Murata ◽  
...  
Keyword(s):  
Abc Transporter ◽  
Molecular System ◽  
Bacterial Species ◽  
Three Dimensional ◽  
Amino Sugar ◽  
Extracellular Matrices ◽  
Dimensional Structure ◽  
Phosphotransferase System ◽  
Streptobacillus Moniliformis ◽  
Genes Encoding

ABSTRACTCertain bacterial species target the polysaccharide glycosaminoglycans (GAGs) of animal extracellular matrices for colonization and/or infection. GAGs such as hyaluronan and chondroitin sulfate consist of repeating disaccharide units of uronate and amino sugar residues, and are depolymerized to unsaturated disaccharides by bacterial extracellular or cell-surface polysaccharide lyase. The disaccharides are degraded and metabolized by cytoplasmic enzymes such as unsaturated glucuronyl hydrolase, isomerase, and reductase. The genes encoding these enzymes are assembled to form a GAG genetic cluster. Here, we demonstrate theStreptococcus agalactiaephosphotransferase system (PTS) for import of unsaturated hyaluronan disaccharide.S. agalactiaeNEM316 was found to depolymerize and assimilate hyaluronan, whereas its mutant with a disruption in PTS genes included in the GAG cluster was unable to grow on hyaluronan, while retaining the ability to depolymerize hyaluronan. Using toluene-treated wild-type cells, the PTS import activity of unsaturated hyaluronan disaccharide was significantly higher than that observed in the absence of the substrate. In contrast, the PTS mutant was unable to import unsaturated hyaluronan disaccharide, indicating that the corresponding PTS is the only importer of fragmented hyaluronan, which is suitable for PTS to phosphorylate the substrate at the C-6 position. The three-dimensional structure of streptococcal EIIA, one of the PTS components, was found to contain a Rossman-fold motif by X-ray crystallization. Docking of EIIA with another component EIIB by modeling provided structural insights into the phosphate transfer mechanism. This study is the first to identify the substrate (unsaturated hyaluronan disaccharide) recognized and imported by the streptococcal PTS.IMPORTANCE (118/120 words)The PTS identified in this work imports sulfate group-free unsaturated hyaluronan disaccharide as a result of the phosphorylation of the substrate at the C-6 position.S. agalactiaecan be indigenous to animal hyaluronan-rich tissues owing to the bacterial molecular system for fragmentation, import, degradation, and metabolism of hyaluronan. Distinct from hyaluronan, most GAGs, which are sulfated at the C-6 position, are unsuitable for PTS due to its inability to phosphorylate the substrate. More recently, we have identified a solute-binding protein-dependent ABC transporter in a pathogenicStreptobacillus moniliformisas an importer of sulfated and non-sulfated fragmented GAGs without any substrate modification. Our findings regarding PTS and ABC transporter shed light on bacterial clever colonization/infection system targeting various animal GAGs.

scholarly journals A forty-year journey in plant research: original contributions to flavonoid biochemistry

2005 ◽  
Vol 83 (5) ◽  
pp. 433-450 ◽  
Author(s):  
Ragai K Ibrahim
Keyword(s):  
Three Dimensional ◽  
Biological Significance ◽  
Flavonoid Biosynthesis ◽  
Dimensional Structure ◽  
Enzymatic Reactions ◽  
Research Career ◽  
Substrate Preferences ◽  
Genes Encoding ◽  
The Common ◽  
New Compounds

This review highlights original contributions by the author to the field of flavonoid biochemistry during his research career of more than four decades. These include elucidation of novel aspects of some of the common enzymatic reactions involved in the later steps of flavonoid biosynthesis, with emphasis on methyltransferases, glucosyltransferases, sulfotransferases, and an oxoglutarate-dependent dioxygenase, as well as cloning, and inferences about phylogenetic relationships, of the genes encoding some of these enzymes. The three-dimensional structure of a flavonol O-methyltransferase was studied through homology-based modeling, using a caffeic acid O-methyltransferase as a template, to explain their strict substrate preferences. In addition, the biological significance of enzymatic prenylation of isoflavones, as well as their role as phytoanticipins and inducers of nodulation genes, are emphasized. Finally, the potential application of knowledge about the genes encoding these enzyme reactions is discussed in terms of improving plant productivity and survival, modification of flavonoid profiles, and the search for new compounds with pharmaceutical and (or) nutraceutical value.Key words: flavonoid enzymology, metabolite localization, gene cloning, 3-D structure, phylogeny.

scholarly journals Crystal structure of the MIF4G domain of the Trypanosoma cruzi translation initiation factor EIF4G5

2019 ◽  
Vol 75 (12) ◽  
pp. 738-743
Author(s):  
Lucca Pietro Camillo dos Santos ◽  
Bruno Moisés de Matos ◽  
Brenda Cecilia de Maman Ribeiro ◽  
Nilson Ivo Tonin Zanchin ◽  
Beatriz Gomes Guimarães
Keyword(s):  
Crystal Structure ◽  
Translation Initiation ◽  
Specific Interaction ◽  
Three Dimensional ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Dimensional Structure ◽  
Initiation Factors ◽  
Genes Encoding ◽  
Rna Complexes

Kinetoplastida, a class of early-diverging eukaryotes that includes pathogenic Trypanosoma and Leishmania species, display key differences in their translation machinery compared with multicellular eukaryotes. One of these differences involves a larger number of genes encoding eIF4E and eIF4G homologs and the interaction pattern between the translation initiation factors. eIF4G is a scaffold protein which interacts with the mRNA cap-binding factor eIF4E, the poly(A)-binding protein, the RNA helicase eIF4A and the eIF3 complex. It contains the so-called middle domain of eIF4G (MIF4G), a multipurpose adaptor involved in different protein–protein and protein–RNA complexes. Here, the crystal structure of the MIF4G domain of T. cruzi EIF4G5 is described at 2.4 Å resolution, which is the first three-dimensional structure of a trypanosomatid MIF4G domain to be reported. Structural comparison with IF4G homologs from other eukaryotes and other MIF4G-containing proteins reveals differences that may account for the specific interaction mechanisms of MIF4G despite its highly conserved overall fold.

scholarly journals Carboxy-Terminal Processing of the Large Subunit of [Fe] Hydrogenase from Desulfovibrio desulfuricans ATCC 7757

1999 ◽  
Vol 181 (9) ◽  
pp. 2947-2952 ◽  
Author(s):  
E. Claude Hatchikian ◽  
Valérie Magro ◽  
Nicole Forget ◽  
Yvain Nicolet ◽  
Juan C. Fontecilla-Camps
Keyword(s):  
Large Subunit ◽  
Three Dimensional ◽  
Desulfovibrio Desulfuricans ◽  
Small Subunit ◽  
Dimensional Structure ◽  
Desulfovibrio Vulgaris ◽  
Closely Related Species ◽  
Genes Encoding ◽  
Reported Data ◽  
Carboxy Terminal

ABSTRACT hydA and hydB, the genes encoding the large (46-kDa) and small (13.5-kDa) subunits of the periplasmic [Fe] hydrogenase from Desulfovibrio desulfuricans ATCC 7757, have been cloned and sequenced. The deduced amino acid sequence of the genes product showed complete identity to the sequence of the well-characterized [Fe] hydrogenase from the closely related speciesDesulfovibrio vulgaris Hildenborough (G. Voordouw and S. Brenner, Eur. J. Biochem. 148:515–520, 1985). The data show that in addition to the well-known signal peptide preceding the NH2 terminus of the mature small subunit, the large subunit undergoes a carboxy-terminal processing involving the cleavage of a peptide of 24 residues, in agreement with the recently reported data on the three-dimensional structure of the enzyme (Y. Nicolet, C. Piras, P. Legrand, E. C. Hatchikian, and J. C. Fontecilla-Camps, Structure 7:13–23, 1999). We suggest that this C-terminal processing is involved in the export of the protein to the periplasm.

Three-dimensional structure of a regular bacterial surface layer: The HPI-layer of Deinococcus radiodurans

1983 ◽  
Vol 41 ◽  
pp. 438-439
Author(s):  
W. Baumeister ◽  
M. Hahn ◽  
W.O. Saxton
Keyword(s):  
Outer Membrane ◽  
Protein Interactions ◽  
Deinococcus Radiodurans ◽  
Bacterial Species ◽  
Hexagonal Lattice ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Protein Protein Interactions ◽  
Bacterial Surface ◽  
Freeze Dried

Regularly organized surface (RS) layers are a feature common to many bacterial species; they are clearly more abundant than was anticipated even a few years ago. The RS-layers are believed to fulfil a variety of functions in the interaction between the cell and its environment (see e.g. [1]). The so-called HPI-layer of the radiotolerant bacterium Deinococcus radiodurans is a typical example of such a layer: It is composed of a single polypeptide species (Mr 105 kDa) arranged on a hexagonal lattice to form a network that covers the entire surface of the bacterium; it is associated with the outer membrane via hydrophobic protein-protein interactions.Isolated HPI-layer sheets, released from the outer membrane by detergent treatment, have been studied in the electron microscope making extensive use of the present arsenal of preparation techniques: negative staining, (auro- thio)glucose embedding, freeze-dried/unstained, freeze-dried/metal shadowed etc.Because of the notorious problem of lattice imperfections image processing usually followed the strategy of correlation averaging as outlined in some detail elsewhere.

scholarly journals Sulfate-Binding Protein (Sbp) from Xanthomonas citri: Structure and Functional Insights

2017 ◽  
Vol 30 (7) ◽  
pp. 578-588 ◽  
Author(s):  
Cristiane Tambascia Pereira ◽  
Cássia Roesler ◽  
Jéssica Nascimento Faria ◽  
Melissa Regina Fessel ◽  
Andrea Balan
Keyword(s):  
Abc Transporter ◽  
Structural Changes ◽  
Binding Protein ◽  
Functional Characterization ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Xanthomonas Citri ◽  
Canker Disease

The uptake and transport of sulfate in bacteria is mediated by an ATP-binding cassette transporter (ABC transporter) encoded by sbpcysUWA genes, whose importance has been widely demonstrated due to their relevance in cysteine synthesis and bacterial growth. In Xanthomonas citri, the causative agent of canker disease, the expression of components from this ABC transporter and others related to uptake of organic sulfur sources has been shown during in vitro growth cultures. In this work, based on gene reporter and proteomics analyses, we showed the activation of the promoter that controls the sbpcysUWA operon in vitro and in vivo and the expression of sulfate-binding protein (Sbp), a periplasmic-binding protein, indicating that this protein plays an important function during growth and that the transport system is active during Citrus sinensis infection. To characterize Sbp, we solved its three-dimensional structure bound to sulfate at 1.14 Å resolution and performed biochemical and functional characterization. The results revealed that Sbp interacts with sulfate without structural changes, but the interaction induces a significant increasing of protein thermal stability. Altogether, the results presented in this study show the evidence of the functionality of the ABC transporter for sulfate in X. citri and its relevance during infection.

scholarly journals Monitoring conformational changes during the catalytic cycle of OpuAA, the ATPase subunit of the ABC transporter OpuA from Bacillus subtilis

2008 ◽  
Vol 412 (2) ◽  
pp. 233-244 ◽  
Author(s):  
Carsten Horn ◽  
Stefan Jenewein ◽  
Britta Tschapek ◽  
Werner Bouschen ◽  
Sabine Metzger ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Abc Transporter ◽  
Conformational Changes ◽  
Compatible Solutes ◽  
Three Dimensional ◽  
Fine Tuning ◽  
Transport Systems ◽  
Dimensional Structure ◽  
Atpase Subunit ◽  
Accessory Domain

The ABC transporter (ATP-binding-cassette transporter) OpuA is one of five membrane transport systems in Bacillus subtilis that mediate osmoprotection by importing compatible solutes. Just like all bacterial and archaeal ABC transporters that catalyse the import of substrates, OpuA (where Opu is osmoprotectant uptake) is composed of an ATPase subunit (OpuAA), a transmembrane subunit (OpuAB) and an extracellular substrate-binding protein (OpuAC). In contrast with many well-known ABC-ATPases, OpuAA is composed not only of a catalytic and a helical domain but also of an accessory domain located at its C-terminus. The paradigm of such an architecture is MalK, the ABC-ATPase of the maltose importer of Escherichia coli, for which detailed structural and functional information is available. In the present study, we have applied solution FRET (Förster resonance energy transfer) techniques using two single cysteine mutants to obtain initial structural information on the architecture of the OpuAA dimer in solution. Analysing our results in detail and comparing them with the existing MalK structures revealed that the catalytic and helical domains adopted an arrangement similar to those of MalK, whereas profound differences in the three-dimensional orientation of the accessory domain, which contains two CBS (cystathionine β-synthetase) domains, were observed. These results shed new light on the role of this accessory domain present in a certain subset of ABC-ATPase in the fine-tuning of three-dimensional structure and biological function.

scholarly journals Characterization of a Novel Glucosamine-6-Phosphate Deaminase from a Hyperthermophilic Archaeon

2005 ◽  
Vol 187 (20) ◽  
pp. 7038-7044 ◽  
Author(s):  
Takeshi Tanaka ◽  
Fumikazu Takahashi ◽  
Toshiaki Fukui ◽  
Shinsuke Fujiwara ◽  
Haruyuki Atomi ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Abc Transporter ◽  
Catalytic Properties ◽  
Sugar Metabolism ◽  
Amino Sugar ◽  
Hyperthermophilic Archaeon ◽  
Chitin Degradation ◽  
Genes Encoding ◽  
Activity Dependent

ABSTRACT A key step in amino sugar metabolism is the interconversion between fructose-6-phosphate (Fru6P) and glucosamine-6-phosphate (GlcN6P). This conversion is catalyzed in the catabolic and anabolic directions by GlcN6P deaminase and GlcN6P synthase, respectively, two enzymes that show no relationship with one another in terms of primary structure. In this study, we examined the catalytic properties and regulatory features of the glmD gene product (GlmD Tk ) present within a chitin degradation gene cluster in the hyperthermophilic archaeon Thermococcus kodakaraensis KOD1. Although the protein GlmD Tk was predicted as a probable sugar isomerase related to the C-terminal sugar isomerase domain of GlcN6P synthase, the recombinant GlmD Tk clearly exhibited GlcN6P deaminase activity, generating Fru6P and ammonia from GlcN6P. This enzyme also catalyzed the reverse reaction, the ammonia-dependent amination/isomerization of Fru6P to GlcN6P, whereas no GlcN6P synthase activity dependent on glutamine was observed. Kinetic analyses clarified the preference of this enzyme for the deaminase reaction rather than the reverse one, consistent with the catabolic function of GlmD Tk . In T. kodakaraensis cells, glmDTk was polycistronically transcribed together with upstream genes encoding an ABC transporter and a downstream exo-β-glucosaminidase gene (glmATk ) within the gene cluster, and their expression was induced by the chitin degradation intermediate, diacetylchitobiose. The results presented here indicate that GlmD Tk is actually a GlcN6P deaminase functioning in the entry of chitin-derived monosaccharides to glycolysis in this hyperthermophile. This enzyme is the first example of an archaeal GlcN6P deaminase and is a structurally novel type distinct from any previously known GlcN6P deaminase.

scholarly journals The N Terminus of the Escherichia coli Transcription Activator MalT Is the Domain of Interaction with MalY

2002 ◽  
Vol 184 (11) ◽  
pp. 3069-3077 ◽  
Author(s):  
Anja Schlegel ◽  
Olivier Danot ◽  
Evelyne Richet ◽  
Thomas Ferenci ◽  
Winfried Boos
Keyword(s):  
Escherichia Coli ◽  
Gel Filtration ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Structural Domain ◽  
Transcription Activator ◽  
Acetyl Esterase ◽  
Regulatory Circuits ◽  
Genes Encoding

ABSTRACT The maltose system of Escherichia coli consists of a number of genes encoding proteins involved in the uptake and metabolism of maltose and maltodextrins. The system is positively regulated by MalT, its transcriptional activator. MalT activity is controlled by two regulatory circuits: a positive one with maltotriose as effector and a negative one involving several proteins. MalK, the ATP-hydrolyzing subunit of the cognate ABC transporter, MalY, an enzyme with the activity of a cystathionase, and Aes, an acetyl esterase, phenotypically act as repressors of MalT activity. By in vivo titration assays, we have shown that the N-terminal 250 amino acids of MalT contain the interaction site for MalY but not for MalK. This was confirmed by gel filtration analysis, where MalY was shown to coelute with the N-terminal MalT structural domain. Mutants in MalT causing elevated mal gene expression in the absence of exogenous maltodextrins were tested in their response to the three repressors. The different MalT mutations exhibited a various degree of sensitivity towards these repressors, but none was resistant to all of them. Some of them became nearly completely resistant to Aes while still being sensitive to MalY. These mutations are located at positions 38, 220, 243, and 359, most likely defining the interaction patch with Aes on the three-dimensional structure of MalT.

scholarly journals LuxS quorum sensing system, its protein modeling and active-binding sites and phylogenetic analysis from Aeromonas hydrophila

2017 ◽  
Author(s):  
Farman Ali ◽  
Zujie Yao ◽  
Wanxin Li ◽  
Sun Lina ◽  
Wenxiong Lin ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Binding Sites ◽  
Sequence Similarity ◽  
Bacterial Species ◽  
Three Dimensional ◽  
Alpha Helix ◽  
Zinc Ion ◽  
Dimensional Structure ◽  
Wide Range ◽  
Range Of Functions

LuxS is commonly found in various bacterial species, like A. hydrophila which causes infection in fish, shrimps, and prawns and is a great threat to aquaculture industry as well as public health. It is an essential enzyme and highly conserved in various bacterial species, and has a wide range of functions such as involved in quorum sensing (QS), sporulation, virulence and synthesis of biofilm. This study focused on the prediction of 3D-sturcture of LuxS by template similarity and its ligand binding sites analysis to define its structure-function relationship. Primary structure analysis of LuxS examined that about 42% of residues content are alpha-helix, which makes it stable for three-dimensional structure homology. For the con struction of homology modeling of LuxS, crystal structure (5e68.1.A) has been used as a template and Swiss model as a work space. The validation of model by ProSA, SAVES, PROCHECK, PROSAII and RMSD. All results analysis shows that refined model is reliable and it has78.11% amino acids sequence similarity with the template,0.4Åas RMSD, and Z-score is -6.21 and Ramachandran plot analysis shows that 83.4% of residues found in the most favored regions where only 0.4% falls into the disallowed regions. Zinc ion ligand was predicted with highest MAMMOTH score and its binding residues His-54, His-58 and Cys-128 were analyzed by COACH-Meta server. LuxS phylogeny was constructed by sequences and structures of the most similar sequences were analyzed. In silico, the information has been generated in this work expects to be the first step towards the structure determination of LuxS in A. hydrophila.

scholarly journals LuxS quorum sensing system, its protein modeling and active-binding sites and phylogenetic analysis from Aeromonas hydrophila

2017 ◽  
Author(s):  
Farman Ali ◽  
Zujie Yao ◽  
Wanxin Li ◽  
Sun Lina ◽  
Wenxiong Lin ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Binding Sites ◽  
Sequence Similarity ◽  
Bacterial Species ◽  
Three Dimensional ◽  
Alpha Helix ◽  
Zinc Ion ◽  
Dimensional Structure ◽  
Wide Range ◽  
Range Of Functions

LuxS is commonly found in various bacterial species, like A. hydrophila which causes infection in fish, shrimps, and prawns and is a great threat to aquaculture industry as well as public health. It is an essential enzyme and highly conserved in various bacterial species, and has a wide range of functions such as involved in quorum sensing (QS), sporulation, virulence and synthesis of biofilm. This study focused on the prediction of 3D-sturcture of LuxS by template similarity and its ligand binding sites analysis to define its structure-function relationship. Primary structure analysis of LuxS examined that about 42% of residues content are alpha-helix, which makes it stable for three-dimensional structure homology. For the con struction of homology modeling of LuxS, crystal structure (5e68.1.A) has been used as a template and Swiss model as a work space. The validation of model by ProSA, SAVES, PROCHECK, PROSAII and RMSD. All results analysis shows that refined model is reliable and it has78.11% amino acids sequence similarity with the template,0.4Åas RMSD, and Z-score is -6.21 and Ramachandran plot analysis shows that 83.4% of residues found in the most favored regions where only 0.4% falls into the disallowed regions. Zinc ion ligand was predicted with highest MAMMOTH score and its binding residues His-54, His-58 and Cys-128 were analyzed by COACH-Meta server. LuxS phylogeny was constructed by sequences and structures of the most similar sequences were analyzed. In silico, the information has been generated in this work expects to be the first step towards the structure determination of LuxS in A. hydrophila.

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