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Souza JGS, Bertolini M, Thompson A, Mansfield JM, Grassmann AA, Maas K, Caimano MJ, Barao VAR, Vickerman MM, Dongari-Bagtzoglou A. Role of glucosyltransferase R in biofilm interactions between Streptococcus oralis and Candida albicans. THE ISME JOURNAL 2020; 14:1207-1222. [PMID: 32042100 PMCID: PMC7174356 DOI: 10.1038/s41396-020-0608-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 01/08/2020] [Accepted: 01/30/2020] [Indexed: 02/08/2023]
Abstract
Streptococcal glucosyltransferases (Gtf) synthesize α-glucan exopolymers which contribute to biofilm matrix. Streptococcus oralis interacts with the opportunistic pathogen Candida albicans to form hypervirulent biofilms. S. oralis 34 has a single gtf gene (gtfR). However, the role of gtfR in single and mixed species biofilms with C. albicans has never been examined. A gtfR deletion mutant, purified GtfR, and recombinant GtfR glucan-binding domain were tested in single and mixed biofilms on different substrata in vitro. A mouse oral infection model was also used. We found that in single species biofilms growing with sucrose on abiotic surfaces S. oralis gtfR increased biofilm matrix, but not bacterial biomass. In biofilms with C. albicans, S. oralis encoding gtfR showed increased bacterial biomass on all surfaces. C. albicans had a positive effect on α-glucan synthesis, and α-glucans increased C. albicans accretion on abiotic surfaces. In single and mixed infection of mice receiving sucrose S. oralis gtfR enhanced mucosal burdens. However, sucrose had a negative impact on C. albicans burdens and reduced S. oralis burdens in co-infected mice. Our data provide new insights on the GtfR-mediated interactions between the two organisms and the influence of biofilm substratum and the mucosal environment on these interactions.
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Affiliation(s)
- João Gabriel Silva Souza
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT, USA
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, São Paulo, Brazil
| | - Martinna Bertolini
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT, USA
| | - Angela Thompson
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT, USA
| | - Jillian M Mansfield
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY, USA
| | - André Alex Grassmann
- Departments of Medicine, Pediatrics and Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| | - Kendra Maas
- Microbial Analysis, Resources, and Services Core, University of Connecticut, Storrs, CT, USA
| | - Melissa J Caimano
- Departments of Medicine, Pediatrics and Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| | - Valentim Adelino Ricardo Barao
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, São Paulo, Brazil
| | - M Margaret Vickerman
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY, USA.
| | - Anna Dongari-Bagtzoglou
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT, USA.
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Vickerman MM, Mansfield JM, Zhu M, Walters KS, Banas JA. Codon-optimized fluorescent mTFP and mCherry for microscopic visualization and genetic counterselection of streptococci and enterococci. J Microbiol Methods 2015; 116:15-22. [PMID: 26122309 PMCID: PMC4522221 DOI: 10.1016/j.mimet.2015.06.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 06/19/2015] [Accepted: 06/19/2015] [Indexed: 01/20/2023]
Abstract
Despite the powerful potential of fluorescent proteins for labeling bacteria, their use has been limited in multi-species oral biofilm models. Fermentative metabolism by streptococcal species that initiate biofilm colonization results in an acidic, reduced microenvironment that may limit the activities of some fluorescent proteins which are influenced by pH and oxygen availability. The need to reliably distinguish morphologically similar strains within biofilms was the impetus for this work. Teal fluorescent protein (mTFP1) and red fluorescent protein (mCherry) were chosen because their fluorescent properties made them promising candidates. Since tRNA availability has been implicated in efficient translation of sufficient quantities of protein for maximum fluorescence, a streptococcal codon optimization approach was used. DNA was synthesized to encode either protein using codons most frequently used in streptococci; each coding region was preceded by an engineered ribosomal binding site and restriction sites for cloning a promoter. Plasmids carrying this synthesized DNA under control of the Streptococcus mutans lactate dehydrogenase promoter conferred fluorescence to nine representative streptococcal and two Enterococcus faecalis strains. Further characterization in Streptococcus gordonii showed that mTFP1 and mCherry expressions could be detected in cells grown planktonically, in biofilms, or in colonies on agar when expressed on an extrachromosomal plasmid or in single copy integrated into the chromosome. This latter property facilitated counterselection of chromosomal mutations demonstrating value for bacterial strain construction. Fluorescent and non-fluorescent bacteria were distinguishable at acidic pH. These codon-optimized versions of mTFP1 and mCherry have promising potential for use in multiple experimental applications.
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Affiliation(s)
- M Margaret Vickerman
- Department of Periodontics and Endodontics, University at Buffalo School of Dental Medicine, Buffalo, NY, USA; Department of Oral Biology, University at Buffalo School of Dental Medicine, Buffalo, NY, USA.
| | - Jillian M Mansfield
- Department of Periodontics and Endodontics, University at Buffalo School of Dental Medicine, Buffalo, NY, USA; Department of Oral Biology, University at Buffalo School of Dental Medicine, Buffalo, NY, USA
| | - Min Zhu
- Dows Institute for Research, University of Iowa College of Dentistry, Iowa City, IA, USA
| | - Katherine S Walters
- Central Microscopy Research Facility, University of Iowa, Iowa City, IA, USA
| | - Jeffrey A Banas
- Dows Institute for Research, University of Iowa College of Dentistry, Iowa City, IA, USA
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3
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Zhu F, Zhang H, Wu H. Glycosyltransferase-mediated Sweet Modification in Oral Streptococci. J Dent Res 2015; 94:659-65. [PMID: 25755271 DOI: 10.1177/0022034515574865] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Bacterial glycosyltransferases play important roles in bacterial fitness and virulence. Oral streptococci have evolved diverse strategies to survive and thrive in the carbohydrate-rich oral cavity. In this review, we discuss 2 important biological processes mediated by 2 distinct groups of glycosyltransferases in oral streptococci that are important for bacterial colonization and virulence. The first process is the glycosylation of highly conserved serine-rich repeat adhesins by a series of glycosyltransferases. Using Streptococcus parasanguinis as a model, we highlight new features of several glycosyltransferases that sequentially modify the serine-rich glycoprotein Fap1. Distinct features of a novel glycosyltransferase fold from a domain of unknown function 1792 are contrasted with common properties of canonical glycosyltransferases. The second biological process we cover is involved in building sticky glucan matrix to establish cariogenic biofilms by an important opportunistic pathogen Streptococcus mutans through the action of a family of 3 glucosyltransferases. We focus on discussing the structural feature of this family as a glycoside hydrolase family of enzymes. While the 2 processes are distinct, they all produce carbohydrate-coated biomolecules, which enable bacteria to stick better in the complex oral microbiome. Understanding the making of the sweet modification presents a unique opportunity to develop novel antiadhesion and antibiofilm strategies to fight infections by oral streptococci and beyond.
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Affiliation(s)
- F Zhu
- Departments of Microbiology and Pediatric Dentistry, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - H Zhang
- Departments of Microbiology and Pediatric Dentistry, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - H Wu
- Departments of Microbiology and Pediatric Dentistry, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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Funane K, Ishii T, Terasawa K, Yamamoto T, Kobayashi M. Construction of Chimeric Glucansucrases for Analyzing Substrate-binding Regions That Affect the Structure of Glucan Products. Biosci Biotechnol Biochem 2014; 68:1912-20. [PMID: 15388967 DOI: 10.1271/bbb.68.1912] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A gene that encodes dextransucrase S (dsrS) from Leuconostoc mesenteroides NRRL B-512F encodes a glucansucrase dextransucrase S (DSRS) which mainly produces water-soluble glucan (dextran), while the dsrT5 gene derived from dsrT of the B-512F strain encodes an enzyme dextransucrase T5 (DSRT5), which mainly produces water-insoluble glucan. Tyr340-Asn510 of DSRS and Tyr307-Asn477 of DSRT5 (Site 1), Lys696-Gly768 of DSRS and Lys668-Gly740 of DSRT5 (Site 2), and Asn917-Lys1131 of DSRS and Asn904-Lys1118 of DSRT5 (Site 3) were exchanged and six different chimeric enzymes were constructed. Water-soluble glucan produced by recombinant DSRS was composed of 64% 6-linked glucopyranoside (Glcp), 9% 3,6-linked Glcp, and 13% 4-linked Glcp. Water-insoluble glucan produced by recombinant DSRT5 was composed of 47% 6-linked Glcp and 43% 3-linked Glcp. All of the chimeric enzymes produced glucans different from the ones produced by their parental enzymes. Some of the glucans produced by chimeric enzymes were extremely changed. The Site 1 chimeric enzyme of DSRS (STS1) produced water-soluble glucan composed mostly of 6-linked Glcp. That of DSRT5 (TST1) produced water-insoluble glucan composed mostly of 4-linked Glcp. The Site 3 chimeric enzyme of DSRS (STS3) produced mainly water-insoluble glucan, DSRT5 (TST3) produced mainly water-soluble glucans, and all of the glucan fractions consisted of 3-Glcp, 4-Glcp, and 6-Glcp. The amounts of the three linkages in the water-soluble glucan produced by TST3 were about 1:1:1. Site 1 was assumed to be important for making or avoiding making alpha-1,4 linkages, while Site 3 was assumed to be important for determining the kinds of glucosyl linkages made.
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Affiliation(s)
- Kazumi Funane
- National Food Research Institute, Tsukuba, Ibaraki, Japan.
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5
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Ricker A, Vickerman M, Dongari-Bagtzoglou A. Streptococcus gordonii glucosyltransferase promotes biofilm interactions with Candida albicans. J Oral Microbiol 2014; 6:23419. [PMID: 24490004 PMCID: PMC3907680 DOI: 10.3402/jom.v6.23419] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/03/2014] [Accepted: 01/06/2014] [Indexed: 12/02/2022] Open
Abstract
Background Candida albicans co-aggregates with Streptococcus gordonii to form biofilms and their interactions in mucosal biofilms may lead to pathogenic synergy. Although the functions of glucosyltransferases (Gtf) of Mutans streptococci have been well characterized, the biological roles of these enzymes in commensal oral streptococci, such as S. gordonii, in oral biofilm communities are less clear. Objective The objective of this work was to explore the role of GtfG, the single Gtf enzyme of S. gordonii, in biofilm interactions with C. albicans. Design Biofilms were grown under salivary flow in flow cells in vitro, or under static conditions in 96 well plates. A panel of isogenic S. gordonii CH1 gtfG mutants and complemented strains were co-inoculated with C. albicans strain SC5314 to form mixed biofilms. Biofilm accretion and binding interactions between the two organisms were tested. Biofilms were quantified using confocal microscopy or the crystal violet assay. Results The presence of GtfG enhanced dual biofilm accretion, and sucrose supplementation further augmented dual biofilm formation, pointing to a role of newly synthesized glucans. GtfG also promoted binding to C. albicans preformed biofilms. Soluble α-1,6-glucans played a role in these interactions since: 1) a strain producing only soluble glucans (CH107) formed robust dual biofilms under conditions of salivary flow; and 2) the dual biofilm was susceptible to enzymatic breakdown by dextranase which specifically degrades soluble α-1,6-glucans. Conclusion Our work identified a novel molecular mechanism for C. albicans and S. gordonii biofilm interactions, mediated by GtfG. This protein promotes early biofilm binding of S. gordonii to C. albicans which leads to increased accretion of streptococcal cells in mixed biofilms. We also showed that soluble glucans, with α-1,6-linkages, promoted inter-generic adhesive interactions.
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Affiliation(s)
- Austin Ricker
- School of Dental Medicine, University of Connecticut Health Center, Farmington, CT, USA
| | - Margaret Vickerman
- School of Dental Medicine, State University of New York at Buffalo, Buffalo, NY, USA
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Regulation of recombination between gtfB/gtfC genes in Streptococcus mutans by recombinase A. ScientificWorldJournal 2013; 2013:405075. [PMID: 23476132 PMCID: PMC3586492 DOI: 10.1155/2013/405075] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 01/14/2013] [Indexed: 11/18/2022] Open
Abstract
Streptococcus mutans produces 3 types of glucosyltransferases (GTFs), whose cooperative action is essential for cellular adhesion. The recombinase A (RecA) protein is required for homologous recombination. In our previous study, we isolated several strains with a smooth colony morphology and low GTF activity, characteristics speculated to be derived from the GTF fusions. The purpose of the present study was to investigate the mechanism of those fusions. S. mutans strain MT8148 was grown in the presence of recombinant RecA (rRecA) protein, after which smooth colonies were isolated. The biological functions and sequences of the gtfB and gtfC genes of this as well as other clinical strains were determined. The sucrose-dependent adherence rates of those strains were reduced as compared to that of MT8148. Determination of the sequences of the gtfB and gtfC genes showed that an approximately 3500 bp region was deleted from the area between them. Furthermore, expression of the recA gene was elevated in those strains as compared to MT8148. These results suggest that RecA has an important role in fusions of gtfB and gtfC genes, leading to alteration of colony morphology and reduction in sucrose-dependent adhesion.
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Bowen WH, Koo H. Biology of Streptococcus mutans-derived glucosyltransferases: role in extracellular matrix formation of cariogenic biofilms. Caries Res 2011; 45:69-86. [PMID: 21346355 PMCID: PMC3068567 DOI: 10.1159/000324598] [Citation(s) in RCA: 678] [Impact Index Per Article: 52.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 01/26/2011] [Indexed: 12/18/2022] Open
Abstract
The importance of Streptococcus mutans in the etiology and pathogenesis of dental caries is certainly controversial, in part because excessive attention is paid to the numbers of S. mutans and acid production while the matrix within dental plaque has been neglected. S. mutans does not always dominate within plaque; many organisms are equally acidogenic and aciduric. It is also recognized that glucosyltransferases from S. mutans (Gtfs) play critical roles in the development of virulent dental plaque. Gtfs adsorb to enamel synthesizing glucans in situ, providing sites for avid colonization by microorganisms and an insoluble matrix for plaque. Gtfs also adsorb to surfaces of other oral microorganisms converting them to glucan producers. S. mutans expresses 3 genetically distinct Gtfs; each appears to play a different but overlapping role in the formation of virulent plaque. GtfC is adsorbed to enamel within pellicle whereas GtfB binds avidly to bacteria promoting tight cell clustering, and enhancing cohesion of plaque. GtfD forms a soluble, readily metabolizable polysaccharide and acts as a primer for GtfB. The behavior of soluble Gtfs does not mirror that observed with surface-adsorbed enzymes. Furthermore, the structure of polysaccharide matrix changes over time as a result of the action of mutanases and dextranases within plaque. Gtfs at distinct loci offer chemotherapeutic targets to prevent caries. Nevertheless, agents that inhibit Gtfs in solution frequently have a reduced or no effect on adsorbed enzymes. Clearly, conformational changes and reactions of Gtfs on surfaces are complex and modulate the pathogenesis of dental caries in situ, deserving further investigation.
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Affiliation(s)
- W H Bowen
- Center for Oral Biology, University of Rochester, Rochester, NY 14642, USA.
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8
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Dextransucrase and the mechanism for dextran biosynthesis. Carbohydr Res 2008; 343:3039-48. [DOI: 10.1016/j.carres.2008.09.012] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 09/10/2008] [Accepted: 09/15/2008] [Indexed: 11/22/2022]
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9
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Tanzer JM, Thompson AM, Grant LP, Vickerman MM, Scannapieco FA. Streptococcus gordonii's sequenced strain CH1 glucosyltransferase determines persistent but not initial colonization of teeth of rats. Arch Oral Biol 2007; 53:133-40. [PMID: 17961499 DOI: 10.1016/j.archoralbio.2007.08.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 08/02/2007] [Accepted: 08/03/2007] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Extracellular glucan synthesis from sucrose by Streptococcus gordonii, a major dental plaque biofilm bacterium, is assumed important for colonization of teeth; but this hypothesis is un-tested in vivo. METHODS To do so, we studied an isogenic glucosyltransferase (Gtf)-negative mutant (strain AMS12, gtfG(-)) of S. gordonii sequenced wild type (WT, strain Challis CH1, gtfG(+)), comparing their in vitro abilities to grow in the presence of glucose and sucrose and, in vivo, to colonize and persist on teeth and induce caries in rats. Weanling rats of two breeding colonies, TAN:SPFOM(OM)BR and TAN:SPFOM(OMASF)BR, eating high sucrose diet, were inoculated with either the WT (gtfG(+)), its isogenic gtfG(-) mutant, or reference strains of Streptococcus mutans. Control animals were not inoculated. RESULTS In vitro, the gtfG(-) strain grew at least as rapidly in the presence of sucrose as its WT gtfG(+) progenitor, but formed soft colonies on sucrose agar, consistent with its lack of insoluble glucan synthesis. It also had a higher growth yield due apparently to its inability to channel carbon flow into extracellular glucan. In vivo, the gtfG(-) mutant initially colonized as did the WT but, unlike the WT, failed to persist on the teeth as shown over time. By comparison to three S. mutans strains, S. gordonii WT, despite its comparable ecological success on the teeth, was associated with only modest caries induction. Failure of the gtfG(-) mutant to persistently colonize was associated with slight diminution of caries scores by comparison with its gtfG(+) WT. CONCLUSIONS Initial S. gordonii colonization does not depend on Gtf-G synthesis; rather, Gtf-G production determines S. gordonii's ability to persist on the teeth of sucrose-fed rats. S. gordonii appears weakly cariogenic by comparison with S. mutans reference strains.
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Affiliation(s)
- J M Tanzer
- Division of Oral Medicine, Department of Oral Health and Diagonistic Science, University of Connecticut Health Center, Farmington, CT 06030-1605, USA.
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Banas JA, Fountain TL, Mazurkiewicz JE, Sun K, Vickerman MM. Streptococcus mutans glucan-binding protein-A affects Streptococcus gordonii biofilm architecture. FEMS Microbiol Lett 2006; 267:80-8. [PMID: 17166223 PMCID: PMC1780135 DOI: 10.1111/j.1574-6968.2006.00557.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The glucan-binding protein-A (GbpA) of Streptococcus mutans has been shown to contribute to the architecture of glucan-dependent biofilms formed by this species and influence virulence in a rat model. As S. mutans synthesizes multiple glucosyltransferases and nonglucosyltransferase glucan-binding proteins (GBPs), it is possible that there is functional redundancy that overshadows the full extent of GbpA contributions to S. mutans biology. Glucan-associated properties such as adhesion, aggregation, and biofilm formation were examined independently of other S. mutans GBPs by cloning the gbpA gene into a heterologous host, Streptococcus gordonii, and derivatives with altered or diminished glucosyltransferase activity. The presence of GbpA did not alter dextran-dependent aggregation nor the initial sucrose-dependent adhesion of S. gordonii. However, expression of GbpA altered the biofilm formed by wild-type S. gordonii as well as the biofilm formed by strain CH107 that produced primarily alpha-1,6-linked glucan. Expression of gbpA did not alter the biofilm formed by strain DS512, which produced significantly lower quantities of parental glucan. These data are consistent with a role for GbpA in facilitating the development of biofilms that harbor taller microcolonies via binding to alpha-1,6-linkages within glucan. The magnitude of the GbpA effect appears to be dependent on the quantity and linkage of available glucan.
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Affiliation(s)
- Jeffrey A Banas
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, USA.
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11
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Giomarelli B, Visai L, Hijazi K, Rindi S, Ponzio M, Iannelli F, Speziale P, Pozzi G. Binding ofStreptococcus gordoniito extracellular matrix proteins. FEMS Microbiol Lett 2006; 265:172-7. [PMID: 17038048 DOI: 10.1111/j.1574-6968.2006.00479.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Knock-out mutants of Streptococcus gordonii Challis were constructed and assayed for binding to extracellular matrix proteins (EMPs) by enzyme-linked immunosorbent assay (ELISA). It was shown that (i) the mutant lacking the cell wall polysaccharide receptor could no longer bind type I and type II collagen, (ii) the mutant lacking the fibronectin-binding proteins CshA and FbpA was also strongly impaired in collagen binding and (iii) the mutant lacking the methionine sulfoxide reductase MsrA was significantly impaired in fibronectin binding. Our results indicate that binding to EMPs by S. gordonii is a multifactorial process controlled by genes located at three different chromosomal sites.
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Affiliation(s)
- Barbara Giomarelli
- Laboratory of Molecular Microbiology and Biotechnology (LAMMB), Department of Molecular Biology, University of Siena, Siena, Italy
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Korakli M, Vogel RF. Structure/function relationship of homopolysaccharide producing glycansucrases and therapeutic potential of their synthesised glycans. Appl Microbiol Biotechnol 2006; 71:790-803. [PMID: 16724190 DOI: 10.1007/s00253-006-0469-4] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Revised: 04/12/2006] [Accepted: 04/19/2006] [Indexed: 10/24/2022]
Abstract
The capability of lactic acid bacteria (LAB) to produce exopoly- and oligosaccharides was and is the subject of expanding research efforts. Due to their physicochemical properties and health-promoting potential, exopoly- and oligosaccharides from food-grade LAB can be used in the food and other industries and may have additional medical applications. In the last years, many LAB have been screened for their ability to produce exopoly- and oligosaccharides, and several glycosyltransferases involved in their biosynthesis have been characterised at biochemical and genetic levels. These research efforts aim to exploit the full potential of these organisms and to understand the structure/function relationship of glycosyltransferases. The latter knowledge is a prerequisite for the production of tailored exopoly- and oligosaccharides for the diverse applications. This review will survey the results of recent works on the structure/function relationship of homopolysaccharide producing glycosyltransferases and the therapeutic potential of their synthesised exopoly- and oligosaccharides.
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Affiliation(s)
- Maher Korakli
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, Weihenstephaner Steig 16, 85350, Freising, Germany.
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van Hijum SAFT, Kralj S, Ozimek LK, Dijkhuizen L, van Geel-Schutten IGH. Structure-function relationships of glucansucrase and fructansucrase enzymes from lactic acid bacteria. Microbiol Mol Biol Rev 2006; 70:157-76. [PMID: 16524921 PMCID: PMC1393251 DOI: 10.1128/mmbr.70.1.157-176.2006] [Citation(s) in RCA: 316] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lactic acid bacteria (LAB) employ sucrase-type enzymes to convert sucrose into homopolysaccharides consisting of either glucosyl units (glucans) or fructosyl units (fructans). The enzymes involved are labeled glucansucrases (GS) and fructansucrases (FS), respectively. The available molecular, biochemical, and structural information on sucrase genes and enzymes from various LAB and their fructan and alpha-glucan products is reviewed. The GS and FS enzymes are both glycoside hydrolase enzymes that act on the same substrate (sucrose) and catalyze (retaining) transglycosylation reactions that result in polysaccharide formation, but they possess completely different protein structures. GS enzymes (family GH70) are large multidomain proteins that occur exclusively in LAB. Their catalytic domain displays clear secondary-structure similarity with alpha-amylase enzymes (family GH13), with a predicted permuted (beta/alpha)(8) barrel structure for which detailed structural and mechanistic information is available. Emphasis now is on identification of residues and regions important for GS enzyme activity and product specificity (synthesis of alpha-glucans differing in glycosidic linkage type, degree and type of branching, glucan molecular mass, and solubility). FS enzymes (family GH68) occur in both gram-negative and gram-positive bacteria and synthesize beta-fructan polymers with either beta-(2-->6) (inulin) or beta-(2-->1) (levan) glycosidic bonds. Recently, the first high-resolution three-dimensional structures have become available for FS (levansucrase) proteins, revealing a rare five-bladed beta-propeller structure with a deep, negatively charged central pocket. Although these structures have provided detailed mechanistic insights, the structural features in FS enzymes dictating the synthesis of either beta-(2-->6) or beta-(2-->1) linkages, degree and type of branching, and fructan molecular mass remain to be identified.
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Affiliation(s)
- Sacha A F T van Hijum
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, P.O. Box 14, 9750 AA Haren, The Netherlands.
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Funane K, Ishii T, Ono H, Kobayashi M. Changes in linkage pattern of glucan products induced by substitution of Lys residues in the dextransucrase. FEBS Lett 2005; 579:4739-45. [PMID: 16098974 DOI: 10.1016/j.febslet.2005.07.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Revised: 07/16/2005] [Accepted: 07/19/2005] [Indexed: 11/26/2022]
Abstract
Dextransucrase S (DSRS) is the only active glucansucrase that has been found in Leuconostoc mesenteroides NRRL B-512F strain. Native DSRS produces mainly 6-linked glucopyranosyl residue (Glcp), while Escherichia coli recombinant DSRS was observed to produce a glucan consisting of 70% 6-linked Glcp and 15% 3,6-Glcp. Lys residues were introduced at the N-terminal end of the core domain by site-directed mutagenesis. In glucans produced by the one-point mutants T350K and S455K, the amount of 6-linked Glcp was increased to about 85% of the total glucan produced, more similar in structure to native B-512F dextran. The double mutant T350K/S455K produced adhesive, water-insoluble glucan with 77% 6-linked Glcp, 8% 3,6-linked Glcp and 4% 2,6-linked Glcp. The T350K/S455K mutant exhibited a 10-fold increase in glucosyltransferase activity over those of the parental DSRS-His(6) and its T350K and S455K mutants. This is the first report demonstrating a change in the properties of a dextransucrase or a related glucosyltransferase through simple site-directed mutagenesis to create 2,6-linked Glcp.
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Affiliation(s)
- Kazumi Funane
- National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
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15
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Wang B, Kuramitsu HK. Inducible antisense RNA expression in the characterization of gene functions in Streptococcus mutans. Infect Immun 2005; 73:3568-76. [PMID: 15908386 PMCID: PMC1111864 DOI: 10.1128/iai.73.6.3568-3576.2005] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2004] [Revised: 01/06/2005] [Accepted: 02/15/2005] [Indexed: 01/30/2023] Open
Abstract
In order to examine gene function in Streptococcus mutans, we have recently initiated an antisense RNA strategy. Toward this end, we have now constructed and evaluated three Escherichia coli-S. mutans shuttle expression vectors with the fruA and scrB promoters from S. mutans, as well as the tetR-controlled tetO promoter from Staphylococcus aureus. Among these, the tetO/tetR system proved to be the most tightly controlled promoter. By using this shuttle plasmid system, modulation of gene function by inducible antisense RNA expression was demonstrated for comC antisense fragments of different sizes as well as for distinct gtfB antisense fragments. It was demonstrated that the size, but not the relative position, of an antisense DNA fragment is important in mediating the antisense phenomenon. Furthermore, by constructing and screening random DNA libraries with the tet expression shuttle system, 78 growth-retarded transformants harboring antisense DNA fragments were also identified. Almost all of them corresponded to homologous essential genes in other bacteria. In addition, a novel essential gene, the coaE gene, encoding dephospho-coenzyme A kinase, which is involved in the final step of coenzyme A catabolism in S. mutans, was identified and characterized. These results suggest that the antisense RNA strategy can be useful for identifying novel essential genes in S. mutans bacteria as well as further characterizing the physiology (including potential virulence factors) of these organisms.
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Affiliation(s)
- Bing Wang
- Department of Oral Biology, State University of New York at Buffalo, 3435 Main Street, Buffalo, NY 14214, USA
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16
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Kralj S, van Geel-Schutten GH, van der Maarel MJEC, Dijkhuizen L. Biochemical and molecular characterization of Lactobacillus reuteri 121 reuteransucrase. MICROBIOLOGY-SGM 2004; 150:2099-2112. [PMID: 15256553 DOI: 10.1099/mic.0.27105-0] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Lactobacillus reuteri strain 121 uses sucrose for synthesis of a unique, soluble glucan ('reuteran') with mainly alpha-(1-->4) glucosidic linkages. The gene (gtfA) encoding this glucansucrase enzyme had previously been characterized. Here, a detailed biochemical and molecular analysis of the GTFA enzyme is presented. This is believed to be the first report describing reuteransucrase enzyme kinetics and the oligosaccharides synthesized with various acceptors. Alignments of the GTFA sequence with glucansucrases from Streptococcus and Leuconostoc identified conserved amino-acid residues in the catalytic core critical for enzyme activity. Mutants Asp1024Asn, Glu1061Gln and Asp1133Asn displayed 300- to 1000-fold-reduced specific activities. To investigate the role of the relatively large N-terminal variable domain (702 amino acids) and the relatively short C-terminal putative glucan-binding domain (267 amino acids, with 11 YG repeats), various truncated derivatives of GTFA (1781 amino acids) were constructed and characterized. Deletion of the complete N-terminal variable domain of GTFA (GTFA-Delta N) had little effect on reuteran characteristics (size, distribution of glycosidic linkages), but the initial transferase activity of the mutant enzyme increased drastically. Sequential C-terminal deletions (up to six YG repeats) in GTFA-Delta N also had little effect on reuteran characteristics. However, enzyme kinetics drastically changed. Deletion of 7, 8 or 11 YG repeats resulted in dramatic loss of total enzyme activity (43-, 63- and 1000-fold-reduced specific activities, respectively). Characterization of sequential C-terminal deletion mutants of GTFA-Delta N revealed that the C-terminal domain of reuteransucrase has an important role in glucan binding.
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Affiliation(s)
- S Kralj
- Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, 9751 NN, Haren, The Netherlands
- Centre for Carbohydrate Bioengineering (CCB), TNO-University of Groningen, Utrechtseweg 48, 3704 HE, Zeist, The Netherlands
| | - G H van Geel-Schutten
- Centre for Carbohydrate Bioengineering (CCB), TNO-University of Groningen, Utrechtseweg 48, 3704 HE, Zeist, The Netherlands
- Innovative Ingredients and Products Department, TNO-Nutrition and Food Research, Utrechtseweg 48, 3704 HE, Zeist, The Netherlands
| | - M J E C van der Maarel
- Innovative Ingredients and Products Department, TNO-Nutrition and Food Research, Rouaanstraat 27, 9723 CC, Groningen, The Netherlands
- Centre for Carbohydrate Bioengineering (CCB), TNO-University of Groningen, Utrechtseweg 48, 3704 HE, Zeist, The Netherlands
| | - L Dijkhuizen
- Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, 9751 NN, Haren, The Netherlands
- Centre for Carbohydrate Bioengineering (CCB), TNO-University of Groningen, Utrechtseweg 48, 3704 HE, Zeist, The Netherlands
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17
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Idone V, Brendtro S, Gillespie R, Kocaj S, Peterson E, Rendi M, Warren W, Michalek S, Krastel K, Cvitkovitch D, Spatafora G. Effect of an orphan response regulator on Streptococcus mutans sucrose-dependent adherence and cariogenesis. Infect Immun 2003; 71:4351-60. [PMID: 12874312 PMCID: PMC166011 DOI: 10.1128/iai.71.8.4351-4360.2003] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus mutans is the principal acidogenic component of dental plaque that demineralizes tooth enamel, leading to dental decay. Cell-associated glucosyltransferases catalyze the sucrose-dependent synthesis of sticky glucan polymers that, together with glucan binding proteins, promote S. mutans adherence to teeth and cell aggregation. We generated an S. mutans Tn916 transposon mutant, GMS315, which is defective in sucrose-dependent adherence and significantly less cariogenic than the UA130 wild-type progenitor in germfree rats. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting, and N-terminal sequence analysis confirmed the absence of a 155-kDa glucosyltransferase S (Gtf-S) from GMS315 protein profiles. Mapping of the unique transposon insertion in GMS315 revealed disruption of a putative regulatory region located upstream of gcrR, a gene previously described by Sato et al. that shares significant amino acid identity with other bacterial response regulators (Y. Sato, Y. Yamamoto, and H. Kizaki, FEMS Microbiol. Lett. 186: 187-191, 2000). The gcrR regulator, which we call "tarC," does not align with any of the 13 proposed two-component signal transduction systems derived from in silico analysis of the S. mutans genome, but rather represents one of several orphan response regulators in the genome. The results of Northern hybridization and/or real-time reverse transcription-PCR experiments reveal increased expression of both Gtf-S and glucan binding protein C (GbpC) in a tarC knockout mutant (GMS900), thereby supporting the notion that TarC acts as a negative transcriptional regulator. In addition, we noted that GMS900 has altered biofilm architecture relative to the wild type and is hypocariogenic in germfree rats. Taken collectively, these findings support a role for signal transduction in S. mutans sucrose-dependent adherence and aggregation and implicate TarC as a potential target for controlling S. mutans-induced cariogenesis.
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Affiliation(s)
- Vincent Idone
- Department of Biology, Middlebury College, Middlebury Vermont 05753, USA
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18
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Banas JA, Vickerman MM. Glucan-binding proteins of the oral streptococci. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 2003; 14:89-99. [PMID: 12764072 DOI: 10.1177/154411130301400203] [Citation(s) in RCA: 225] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The synthesis of extracellular glucan is an integral component of the sucrose-dependent colonization of tooth surfaces by species of the mutans streptococci. In investigators' attempts to understand the mechanisms of plaque biofilm development, several glucan-binding proteins (GBPs) have been discovered. Some of these, the glucosyltransferases, catalyze the synthesis of glucan, whereas others, designated only as glucan-binding proteins, have affinities for different forms of glucan and contribute to aspects of the biology of their host organisms. The functions of these latter glucan-binding proteins include dextran-dependent aggregation, dextranase inhibition, plaque cohesion, and perhaps cell wall synthesis. In some instances, their glucan-binding domains share common features, whereas in others the mechanism for glucan binding remains unknown. Recent studies indicate that at least some of the glucan-binding proteins modulate virulence and some can act as protective immunogens within animal models. Overall, the multiplicity of GBPs and their aforementioned properties are testimonies to their importance. Future studies will greatly advance the understanding of the distribution, function, and regulation of the GBPs and place into perspective the facets of their contributions to the biology of the oral streptococci.
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Affiliation(s)
- J A Banas
- Center for Immunology and Microbial Disease, Albany Medical College, NY 12208, USA.
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19
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Songy WB, Ruoff KL, Facklam RR, Ferraro MJ, Falkow S. Identification of Streptococcus bovis biotype I strains among S. bovis clinical isolates by PCR. J Clin Microbiol 2002; 40:2913-8. [PMID: 12149351 PMCID: PMC120625 DOI: 10.1128/jcm.40.8.2913-2918.2002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2002] [Accepted: 04/24/2002] [Indexed: 11/20/2022] Open
Abstract
Streptococcus bovis causes 24% of all streptococcal infective endocarditis cases. There are many reports linking both S. bovis bacteremia and endocarditis with various forms of gastrointestinal disease (primarily colonic cancers). S. bovis is divided into two biotypes: I and II. The biotype I strain is much more frequently isolated from patients with endocarditis, gastrointestinal disease, or both. We describe here the isolation of biotype I-specific DNA sequences and the development of a PCR test which can identify S. bovis biotype I strains among S. bovis clinical isolates.
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Affiliation(s)
- Wanda B Songy
- Department of Microbiology and Immunology, Stanford University School of Medicine, California 94305, USA
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20
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Vickerman MM, Minick PE. Genetic analysis of the rgg-gtfG junctional region and its role in Streptococcus gordonii glucosyltransferase activity. Infect Immun 2002; 70:1703-14. [PMID: 11895932 PMCID: PMC127849 DOI: 10.1128/iai.70.4.1703-1714.2002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glucans synthesized by glucosyltransferase enzymes of oral streptococci facilitate bacterial accumulation on surfaces. The Streptococcus gordonii glucosyltransferase gene, gtfG, is positively regulated by rgg, which encodes a putative cytoplasmic protein. The gtfG promoter and ribosomal binding sequences are located within a DNA inverted repeat immediately downstream of rgg. Polycistronic rgg-gtfG as well as rgg- and gtfG-specific transcripts are associated with this chromosomal region. Previous studies have shown that the rgg product acts in trans near the gtfG promoter to increase the level of gtfG transcript, but it does not affect the level of rgg-gtfG transcript. To further analyze regulation by rgg, a series of strain Challis derivatives was constructed and glucosyltransferase activities were determined. Strains in which rgg was separated from gtfG by integrated vector sequences had decreased levels of glucosyltransferase activity; plasmid-borne rgg could not increase activity to parental levels. As expected, strains with chromosomal deletions involving the rgg structural gene and either the rgg or gtfG promoter also showed decreased glucosyltransferase activity. Plasmid-borne rgg could increase glucosyltransferase activity only in strains which had a 36-bp chromosomal region beginning 72 nucleotides upstream of the gtfG transcriptional start site. Results suggest that these nucleotides, located within the 3' end of rgg, are necessary, either by direct involvement in binding or by indirectly affecting secondary structure, for Rgg to increase glucosyltransferase activity. Surprisingly, the presence of the rgg promoter upstream of this 36-bp region significantly increased the effects of plasmid-borne rgg. Implications for glucosyltransferase regulation and applicability to other rgg-like determinants are considered.
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Affiliation(s)
- M M Vickerman
- Department of Oral Surgery and Hospital Dentistry, School of Dentistry, Indiana University, Indianapolis, Indiana 46202, USA.
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21
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Kingston KB, Allen DM, Jacques NA. Role of the C-terminal YG repeats of the primer-dependent streptococcal glucosyltransferase, GtfJ, in binding to dextran and mutan. MICROBIOLOGY (READING, ENGLAND) 2002; 148:549-558. [PMID: 11832518 DOI: 10.1099/00221287-148-2-549] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The recombinant primer-dependent glucosyltransferase GtfJ of Streptococcus salivarius possesses a C-terminal glucan-binding domain composed of eighteen 21 aa YG repeats. By engineering a series of C-terminal truncated proteins, the position at which truncation prevented further mutan synthesis was defined to a region of 43 aa, confirming that not all of the YG motifs were required for the formation of mutan by GtfJ. The role of the YG repeats in glucan binding was investigated in detail. Three proteins consisting of 3.8, 7.2 or 11.0 C-terminal YG repeats were expressed in Escherichia coli. Each of the three purified proteins bound to both the 1,6-alpha-linked glucose residues of dextran and the 1,3-alpha-linked glucose residues of mutan, indicating that a protein consisting of nothing but 3.8 YG repeats could attach to either substrate. Secondary structure predictions of the primary amino acid sequence suggested that 37% of the amino acids were capable of forming a structure such that five regions of beta-sheet were separated by regions capable of forming beta-turns and random coils. CD spectral analysis showed that the purified 3.8 YG protein possessed an unordered secondary structure with some evidence of possible beta-sheet formation and that the protein maintained this relatively unordered structure on binding to dextran.
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Affiliation(s)
- Kim B Kingston
- Institute of Dental Research, Centre for Oral Health, Westmead Hospital, PO Box 533, Wentworthville, NSW 2145, Australia1
| | - Donna M Allen
- Institute of Dental Research, Centre for Oral Health, Westmead Hospital, PO Box 533, Wentworthville, NSW 2145, Australia1
| | - Nicholas A Jacques
- Institute of Dental Research, Centre for Oral Health, Westmead Hospital, PO Box 533, Wentworthville, NSW 2145, Australia1
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22
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Vickerman MM, Mather NM, Minick PE, Edwards CA. Initial characterization of the Streptococcus gordonii htpX gene. ORAL MICROBIOLOGY AND IMMUNOLOGY 2002; 17:22-31. [PMID: 11860552 DOI: 10.1046/j.0902-0055.2001.00000.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Examination of the Streptococcus gordonii chromosomal region, which lies immediately upstream of the glucosyltransferase positive regulatory determinant rgg, revealed two open reading frames. Based on nucleotide sequences, these genes were similar to the Listeria monocytogenes lemA gene, which is involved in antigen presentation, and the Escherichia coli htpX heat shock gene, which has an unknown function. Northern hybridization analysis indicated that S. gordonii lemA and htpX genes were associated with a ca. 1.7-kb polycistronic transcript. Although levels of the lemA/htpX transcript did not increase in response to heat to levels seen with dnaK controls, insertional inactivation of htpX resulted in changes in adhesiveness, cellular morphology and detergent-extractable surface antigens in cells grown at 41 degrees C, implying that htpX may be involved in surface protein expression. Insertional inactivation of lemA and htpX indicated that, despite their proximity to rgg and the structural gene, gtfG, these upstream genes do not affect S. gordonii glucosyltransferase activity.
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Affiliation(s)
- M M Vickerman
- Department of Oral Surgery and Hospital Dentistry, School of Dentistry, Indiana University, 1121 West Michigan Street, Indianapolis, IN 46202, USA
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23
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Vickerman MM, Minick PE, Mather NM. Characterization of the Streptococcus gordonii chromosomal region immediately downstream of the glucosyltransferase gene. MICROBIOLOGY (READING, ENGLAND) 2001; 147:3061-70. [PMID: 11700356 DOI: 10.1099/00221287-147-11-3061] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Streptococcus gordonii glucosyltransferase gene, gtfG, is positively regulated by the upstream determinant rgg. In the present study, two ORFs, transcribed on the opposite DNA strand, were identified immediately downstream of gtfG. The first, designated dsg, shares a convergent putative transcriptional terminator with gtfG, and encodes a predicted 46 kDa transmembrane protein similar to the Yersinia enterocolitica TrsA involved in polysaccharide biosynthesis. Insertional inactivation of dsg resulted in only approximately approximately 60% of the parental level of glucosyltransferase activity. The 870 bp gene 5' to dsg is similar to the gtfG regulatory determinant. Designated rggD, this rgg-like determinant downstream of gtfG encodes a putative 33.6 kDa cytoplasmic protein. Despite their sequence similarity, the functions of rgg and rggD appear specific. Strains in which rggD was insertionally inactivated and strains containing plasmid-borne rggD had parental levels of glucosyltransferase activity. Northern blot hybridization analyses showed approximately 1.3 kb dsg-specific and approximately 1.0 kb rggD-specific mRNA transcripts associated with this region; no polycistronic transcript was observed. Although rgg-like gene products have been demonstrated to function as positive transcriptional regulators of adjacent genes in several streptococcal species, Northern blot analysis suggested that rggD did not influence the transcription of dsg or the divergent downstream ylbN-like determinant under the conditions in the present study. Comparison of this S. gordonii chromosome region to other streptococcal genomes, which do not contain the rgg/rggD-flanked region involved in glucan synthesis, raised intriguing possibilities about the origins of this chromosomal region, and also suggested that rggD might regulate a distally located gene.
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Affiliation(s)
- M M Vickerman
- Department of Oral Surgery and Hospital Dentistry, School of Dentistry, Indiana University, Indianapolis, IN 46202, USA.
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24
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25
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Fujiwara T, Hoshino T, Ooshima T, Sobue S, Hamada S. Purification, characterization, and molecular analysis of the gene encoding glucosyltransferase from Streptococcus oralis. Infect Immun 2000; 68:2475-83. [PMID: 10768934 PMCID: PMC97449 DOI: 10.1128/iai.68.5.2475-2483.2000] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus oralis is a member of the oral streptococcal family and an early-colonizing microorganism in the oral cavity of humans. S. oralis is known to produce glucosyltransferase (GTase), which synthesizes glucans from sucrose. The enzyme was purified chromatographically from a culture supernatant of S. oralis ATCC 10557. The purified enzyme, GTase-R, had a molecular mass of 173 kDa and a pI of 6.3. This enzyme mainly synthesized water-soluble glucans with no primer dependency. The addition of GTase markedly enhanced the sucrose-dependent resting cell adhesion of Streptococcus mutans at a level similar to that found in growing cells of S. mutans. The antibody against GTase-R inhibited the glucan-synthesizing activities of Streptococcus gordonii and Streptococcus sanguis, as well as S. oralis. The N-terminal amino acid sequence of GTase-R exhibited no similarities to known GTase sequences of oral streptococci. Using degenerate PCR primers, an 8.1-kb DNA fragment, carrying the gene (gtfR) coding for GTase-R and its regulator gene (rgg), was cloned and sequenced. Comparison of the deduced amino acid sequence revealed that the rgg genes of S. oralis and S. gordonii exhibited a close similarity. The gtfR gene was found to possess a species-specific nucleotide sequence corresponding to the N-terminal 130 amino acid residues. Insertion of erm or aphA into the rgg or gtfR gene resulted in decreased GTase activity by the organism and changed the colony morphology of these transformants. These results indicate that S. oralis GTase may play an important role in the subsequent colonizing of mutans streptoccoci.
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Affiliation(s)
- T Fujiwara
- Department of Pedodontics, Osaka University Faculty of Dentistry, Suita-Osaka 565-0871, Japan.
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26
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Haas W, Banas JA. Ligand-binding properties of the carboxyl-terminal repeat domain of Streptococcus mutans glucan-binding protein A. J Bacteriol 2000; 182:728-33. [PMID: 10633107 PMCID: PMC94336 DOI: 10.1128/jb.182.3.728-733.2000] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus mutans glucan-binding protein A (GbpA) has sequence similarity in its carboxyl-terminal domain with glucosyltransferases (GTFs), the enzymes responsible for catalyzing the synthesis of the glucans to which GbpA and GTFs can bind and which promote S. mutans attachment to and accumulation on the tooth surface. It was predicted that this C-terminal region, comprised of what have been termed YG repeats, represents the GbpA glucan-binding domain (GBD). In an effort to test this hypothesis and to quantitate the ligand-binding specificities of the GbpA GBD, several fusion proteins were generated and tested by affinity electrophoresis or by precipitation of protein-ligand complexes, allowing the determination of binding constants. It was determined that the 16 YG repeats in GbpA comprise its GBD and that GbpA has a greater affinity for dextran (a water-soluble form of glucan) than for mutan (a water-insoluble form of glucan). Placement of the GBD at the carboxyl terminus was necessary for maximum glucan binding, and deletion of as few as two YG repeats from either end of the GBD reduced the affinity for dextran by over 10-fold. Interestingly, the binding constant of GbpA for dextran was 34-fold higher than that calculated for the GBDs of two S. mutans GTFs, one of which catalyzes the synthesis of water-soluble glucan and the other of which catalyzes the synthesis of water-insoluble glucan.
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Affiliation(s)
- W Haas
- Department of Microbiology, Immunology, and Molecular Genetics, Albany Medical College, Albany, New York 12208, USA
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27
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Monchois V, Arguello-Morales M, Russell RR. Isolation of an active catalytic core of Streptococcus downei MFe28 GTF-I glucosyltransferase. J Bacteriol 1999; 181:2290-2. [PMID: 10094712 PMCID: PMC93647 DOI: 10.1128/jb.181.7.2290-2292.1999] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Truncated variants of GTF-I from Streptococcus downei MFe28 were purified by means of a histidine tag. Sequential deletions showed that the C-terminal domain was not directly involved in the catalytic process but was required for primer activation. A fully active catalytic core of only 100 kDa was isolated.
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Affiliation(s)
- V Monchois
- Department of Oral Biology, The Dental School, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4BW, United Kingdom.
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28
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Monchois V, Reverte A, Remaud-Simeon M, Monsan P, Willemot RM. Effect of Leuconostoc mesenteroides NRRL B-512F dextransucrase carboxy-terminal deletions on dextran and oligosaccharide synthesis. Appl Environ Microbiol 1998; 64:1644-9. [PMID: 9572930 PMCID: PMC106209 DOI: 10.1128/aem.64.5.1644-1649.1998] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Dextransucrase (DSR-S) from Leuconostoc mesenteroides NRRL B-512F is a glucosyltransferase that catalyzes synthesis of soluble dextran from sucrose. In the presence of efficient acceptor molecules, such as maltose, the reaction pathway is shifted toward glucooligosaccharide synthesis. Like glucosyltransferases from oral streptococci, DSR-S possesses a C-terminal glucan-binding domain composed of a series of tandem repeats. In order to determine the role of the C-terminal region of DSR-S in dextran or oligosaccharide synthesis, four DSR-S genes with deletions at the 3' end were constructed. The results showed that the C-terminal region modulated the initial velocity of dextran synthesis but that the K(m) for sucrose, the optimum pH, and the activation energy were all unaffected by the deletions. The C-terminal domain modulated the rate of oligosaccharide synthesis whatever acceptor molecule was used (a good acceptor molecule such as maltose or a poor acceptor molecule such as fructose). The C-terminal domain seemed to play no role in the catalytic process in dextran and oligosaccharide synthesis. In fact, it seems that the role of the C-terminal domain of DSR-S may be to facilitate the translation of dextran and oligosaccharides from the catalytic site.
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Affiliation(s)
- V Monchois
- Centre de Bioingénierie Gilbert Durand, UMR CNRS 5504, LA INRA, INSA, Complexe Scientifique de Rangueil, Toulouse, France
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29
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Abstract
This review explains some of the basic techniques of molecular biology and their application to the study of oral streptococci. Examples of how these techniques have furthered the understanding of streptococcal colonization in health and disease are discussed along with approaches to controlling dental caries that have been made plausible by the knowledge gained using these techniques.
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Affiliation(s)
- N Jacques
- Institute of Dental Research, Sydney
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30
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Vacca-Smith AM, Bowen WH. Binding properties of streptococcal glucosyltransferases for hydroxyapatite, saliva-coated hydroxyapatite, and bacterial surfaces. Arch Oral Biol 1998; 43:103-10. [PMID: 9602288 DOI: 10.1016/s0003-9969(97)00111-8] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The binding specificities of Streptococcus glucosyltransferase (Gtf) B, C and D for hydroxyapatite (HA), saliva-coated hydroxyapatite (SHA), and bacterial surfaces were examined. For HA beads the following values were obtained: (K = affinity; N = number of binding sites) GtfB, K = 46 x 10(5) ml/mumol, N = 0.65 x 10(-6) mumol/m2; GtfC, K = 86 x 10(5) ml/mumol, N = 4.42 x 10(-6) mumol/m2.; GtfD, K = 100 x 10(5) ml/mumol, N = 0.83 x 10(-6) mumol/m2. For SHA beads, the following values were obtained: GtfB, K = 14.7 x 10(5) ml/mumol, N = 1.03 x 10(-6) mumol/m2; GtfC, K = 21.3 x 10(5) ml/mumol, N = 3.66 x 10(-6) mumol/m2; GtfD, K = 1.73 x 10(5) ml/mumol, N = 8.88 x 10(-6) mumol/m2. The binding of GtfB to SHA beads was reduced in the presence of parotid saliva, but the binding of GtfC and D was unaffected. The binding of GtfB to SHA in the presence of parotid saliva supplemented with GtfC and D was reduced when compared with its binding to SHA in the presence of parotid saliva alone. In contrast, te binding of GtfC and SHA was unaffected when parotid saliva was supplemented with the other Gtf enzymes. GtfB bound to several bacterial strains (Strep, mutans GS-5, Actinomyces viscosus OMZ105E and Lactobacillus casei 4646) in an active form, while GtfC and D did not bind to bacterial surfaces. It is concluded that of the three Gtf enzymes, GtfC has the highest affinity for HA and SHA surfaces and can adsorb on the the SHA surface in the presence of the other two enzymes. GtfD also binds to SHA in the presence of the other enzymes but has a very low affinity for the surface. GtfB does not bind to SHA in the presence of the other Gtf enzymes but binds avidly to bacterial surfaces in an active form. Therefore, GtfC most probably binds to apatitic surfaces, while GtfB binds to bacterial surfaces.
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Affiliation(s)
- A M Vacca-Smith
- Department of Dental Research, Rochester Caries Research Center, University of Rochester, New York 14642, USA
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Funane K, Ookura T, Kobayashi M. Glucan binding regions of dextransucrase from Leuconostoc mesenteroides NRRL B-512F. Biosci Biotechnol Biochem 1998; 62:123-7. [PMID: 9501523 DOI: 10.1271/bbb.62.123] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We isolated glucan-binding peptides of a dextransucrase from Leuconostoc mesenteroides B-512F. The dextransucrase was bound to DEAE-Sephadex A-50, Sephadex G-100, and mutan from Streptococcus mutans. Mild trypsin digestion dissociated the enzyme and glucan binding. In the presence of ammonium sulfate, several peptides were bound to glucan after trypsin digestion. Four main mutan-binding peptides were obtained by this method, and those amino acid sequences were analyzed. One of them was identical with the dextran-binding peptide that contains lysine, which was previously isolated by differential chemical modification with o-phthalaldehyde. We also found mutan-binding peptides in sucrose- and dextran-binding regions and a lysine-rich region. Also, there was a peptide similar in sequence to glucan-binding A-repeat of streptococcal glucosyltransferases.
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Affiliation(s)
- K Funane
- National Food Research Institute, Ibaraki, Japan
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Vickerman MM, Clewell DB. Regulation of Streptococcus gordonii glucosyltransferase. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1997; 418:661-4. [PMID: 9331738 DOI: 10.1007/978-1-4899-1825-3_154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- M M Vickerman
- Department of Microbiology and Immunology, School of Medicine, University of Michigan, Ann Arbor, USA
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Vickerman MM, Clewell DB. Deletions in the carboxyl-terminal region of Streptococcus gordonii glucosyltransferase affect cell-associated enzyme activity and sucrose-associated accumulation of growing cells. Appl Environ Microbiol 1997; 63:1667-73. [PMID: 9143100 PMCID: PMC168460 DOI: 10.1128/aem.63.5.1667-1673.1997] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The single glucosyltransferase (GTF) of Streptococcus gordonii Challis CH1 makes alpha 1,3- and alpha 1,6-linked glucans from sucrose. The GTF carboxyl-terminal region has six direct repeats thought to be involved in glucan binding. Strains with defined mutations in this region have been described recently (M. M. Vickerman, M. C. Sulavik, P. E. Minick, and D. B. Clewell, Infect. Immun. 64:5117-5128, 1996). Strain CH107 GTF has three internal direct repeats deleted; the 59 carboxyl-terminal amino acids are identical to those of the parental strain. This deletion resulted in decreased enzyme activity but did not affect the amount of cell-associated GTF protein. The GTFs of strains CH2RPE and CH4RPE have six and eight direct repeats, respectively, but are both missing the 14 carboxyl-terminal amino acids. Strain CH2RPE had significantly decreased levels of cell-associated GTF; this decrease was not obviated by the increased number of direct repeats in strain CH4RPE. Thus, the carboxyl-terminal amino acids appeared to influence the amount of cell-associated GTF more than the direct repeats. The qualitative and quantitative differences in the GTFs did not affect the abilities of these strains to accumulate on hydroxyapatite beads in the absence of sucrose. However, when sucrose was added as a substrate for GTF, the mutant strains were unable to accumulate on these surfaces to the same extent as the parent. These differences in sucrose-associated accumulation may be due to changes in the nature of the glucans produced by the different enzymes and/or cohesive interactions between these glucans and the GTF on the surfaces of the growing streptococci.
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Affiliation(s)
- M M Vickerman
- Department of Microbiology and Immunology, School of Medicine, University of Michigan, Ann Arbor 48109, USA.
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