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A surface protein antigen of Streptococcus mutans having two sets of antigenic determinants (antigens I and II) was purified by column chromatography from culture supernatants of S. mutans serotype c. The protease-resistant component, antigen II, was purified from pronase-digested antigen I/II. The antigens were analyzed chemically and immunologica...
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A panel of 15 murine monoclonal antibodies (MAbs; 14 immunoglobulin G1, 1 immunoglobulin G2a) directed against antigen P1, a major surface protein of mutans streptococci, was prepared. All of these MAbs reacted by the enzyme-linked immunosorbent assay with solubilized wall material from Streptococcus mutans Ingbritt 175 (a serotype c strain which r...
Monoclonal antibodies (McAb) were developed to four protein components of Streptococcus mutans serotype c, some of which are significant in the protection against dental caries. The six McAb used in this investigation support the identities of streptococcal antigens (SA) I/II, I, II, and III. The specificities of these antigenic determinants were e...
Citations
... Streptococcus mutans (S. mutans) is a gram-positive bacterium commonly associated with dental caries, one of the most prevalent human diseases in the world (Lemos et al. 2019). The cell surface-localized protein adhesin called P1 (aka Antigen I/II, AgI/II) mediates sucrose-independent S. mutans adhesion, which facilitates bacterial colonization and biofilm formation on the tooth surface (Russell et al. 1980;Brady et al. 2010;Abranches et al. 2018). P1's C-terminus includes three tandem globular domains (C123) upstream of the LPxTG consensus motif recognized by the transpeptidase SortaseA for attachment of P1 to the peptidoglycan matrix. ...
Adhesin P1 (aka AgI/II) plays a pivotal role in mediating Streptococcus mutans attachment in the oral cavity, as well as in regulating biofilm development and maturation. P1’s naturally occurring truncation product, Antigen II (AgII), adopts both soluble, monomeric and insoluble, amyloidogenic forms within the bacterial life cycle. Monomers are involved in important quaternary interactions that promote cell adhesion and the functional amyloid form promotes detachment of mature biofilms. The heterologous, 51-kD C123 construct comprises most of AgII and was previously characterized by X-ray crystallography. C123 contains three structurally homologous domains, C1, C2, and C3. NMR samples made using the original C123 construct, or its C3 domain, yielded moderately resolved NMR spectra. Using Alphafold, we re-analyzed the P1 sequence to better identify domain boundaries for C123, and in particular the C3 domain. We then generated a more tractable construct for NMR studies of the monomeric form, including quaternary interactions with other proteins. The addition of seven amino acids at the C-terminus greatly improved the spectral dispersion for C3 relative to the prior construct. Here we report the backbone NMR resonance assignments for the new construct and characterize some of its quaternary interactions. These data are in good agreement with the structure predicted by Alphafold, which contains additional β-sheet secondary structure compared to the C3 domain in the C123 crystal structure for a construct lacking the seven C-terminal amino acids. Its quaternary interactions with known protein partners are in good agreement with prior competitive binding assays. This construct can be used for further NMR studies, including protein-protein interaction studies and assessing the impact of environmental conditions on C3 structure and dynamics within C123 as it transitions from monomer to amyloid form.
... The first Ag I/II was characterized in S. mutans where it plays a crucial role in teeth colonisation. It is encoded by the spaP gene (also called pac; Russell et al., 1980). Another S. mutans Ag I/II-related protein, SR (salivary receptor), interacts with salivary glycoproteins adsorbed on the tooth surface (Hajishengallis et al., 1992). ...
Streptococcus anginosus together with S. constellatus and S. intermedius constitute the Streptococcus anginosus group (SAG), until recently considered to be benign commensals of the human mucosa isolated predominantly from oral cavity, but also from upper respiratory, intestinal, and urogenital tracts. For years the virulence potential of SAG was underestimated, mainly due to complications in correct species identification and their assignment to the physiological microbiota. Still, SAG representatives have been associated with purulent infections at oral and non-oral sites resulting in abscesses formation and empyema. Also, life threatening blood infections caused by SAG have been reported. However, the understanding of SAG as potential pathogen is only fragmentary, albeit certain aspects of SAG infection seem sufficiently well described to deserve a systematic overview. In this review we summarize the current state of knowledge of the S. anginosus pathogenicity factors and their mechanisms of action.
... This has been linked to another surface protein, PrgA, which is expressed from the same operon Bhatty et al., 2015;Schmitt et al., 2020). The polymer adhesion domain of SpaP from Class II is also known to be enzymatically released from the cell surface (Russell et al., 1980;Sommer et al., 1987), thereby changing the cell's hydrophobicity properties and facilitating biofilm release (Lee, 1992;Lee et al., 1996). Whether this enzymatic release is specific to these two proteins or something that is more common throughout the classes is not yet known. ...
Surface proteins in Gram-positive bacteria are often involved in biofilm formation, host-cell interactions, and surface attachment. Here we review a protein module found in surface proteins that are often encoded on various mobile genetic elements like conjugative plasmids. This module binds to different types of polymers like DNA, lipoteichoic acid and glucans, and is here termed polymer adhesin domain. We analyze all proteins that contain a polymer adhesin domain and classify the proteins into distinct classes based on phylogenetic and protein domain analysis. Protein function and ligand binding show class specificity, information that will be useful in determining the function of the large number of so far uncharacterized proteins containing a polymer adhesin domain.
... Mike Russell et al. and Roy Russell et al. identified the cell wall antigens I and II in Streptococcus mutans nearly simultaneously over 40 years ago (Russell and Lehner, 1978;Russell, 1979;Russell et al., 1980). Soon after, it was shown that antigen II was actually a breakdown product of antigen I (Kelly et al., 1989), giving rise to their new classification as antigen I/II proteins. ...
... Soon after, it was shown that antigen II was actually a breakdown product of antigen I (Kelly et al., 1989), giving rise to their new classification as antigen I/II proteins. These AgI/II proteins are widely distributed not only among various serotypes within S. mutans (Russell and Lehner, 1978;Russell et al., 1980;Ma et al., 1991), but orthologous proteins sharing similar structure and functions also exist within a number of other streptococcal species (Kelly et al., 1989;Jenkinson and Demuth, 1997;Brady et al., 2010). Due in part to the initial discovery of AgI/II proteins within S. mutans, their contribution to dental caries has been a major focus of AgI/II related research; however, more recent studies have investigated AgI/II proteins in other species and biological niches as well. ...
Streptococci are Gram-positive bacteria that belong to the natural microbiota of humans and animals. Certain streptococcal species are known as opportunistic pathogens with the potential to cause severe invasive disease. Antigen I/II (AgI/II) family proteins are sortase anchored cell surface adhesins that are nearly ubiquitous across streptococci and contribute to many streptococcal diseases, including dental caries, respiratory tract infections, and meningitis. They appear to be multifunctional adhesins with affinities to various host substrata, acting to mediate attachment to host surfaces and stimulate immune responses from the colonized host. Here we will review the literature including recent work that has demonstrated the multifaceted nature of AgI/II family proteins, focusing on their overlapping and distinct functions and their important contribution to streptococcal colonization and disease.
... P1 is visible by electron microscopy of thin sections of S. mutans as a fibrillar layer projecting from the cell wall peptidoglycan [6,7]. It interacts with the salivary agglutinin glycoprotein complex, composed predominantly of the scavenger receptor gp340/DMBT1, host cell matrix proteins and other bacteria to adhere the pathogen to tooth surfaces [8][9][10][11][12][13][14][15]. More recent work also highlights the role P1 plays in adhesive interactions and biofilm development, via specific quaternary structure assembly [16] and amyloid formation [17], further contributing to S. mutans virulence properties. ...
... P1 is a large (185 kDa), modular secreted protein, which is covalently anchored to the S. mutans cell wall peptidoglycan via the transpeptidase SrtA [5]. It was initially purified from bacterial culture supernatants by column chromatography and identified as a dual antigen (AgI/II), with the Ag II moiety representing the protease-resistant component [10]. P1 consists of a 38residue secretion signal sequence, an N-terminal region, three alanine-rich repeats (A1-3), a central socalled variable (V) region where most sequence differences among strains are clustered [18], three proline-rich repeats (P1-3), a C-terminal region consisting of three domains (C1-3), and an LPxTG recognition motif for Sortase A, the transpeptidase that cleaves and covalently attaches its substrate proteins, including P1, to the cell wall peptidoglycan [19] (Fig. 1 panel A). ...
Cell surface‐localized P1 adhesin (aka Antigen I/II or PAc) of the cariogenic bacterium Streptococcus mutans mediates sucrose‐independent adhesion to tooth surfaces. Previous studies showed that P1’s C‐terminal segment (C123, AgII) is also liberated as a separate polypeptide, contributes to cellular adhesion, interacts specifically with intact P1 on the cell surface, and forms amyloid fibrils. Identifying how C123 specifically interacts with P1 at the atomic level is essential for understanding related virulence properties of S. mutans. However, with sizes of ~ 51 and ~ 185 kDa, respectively, C123 and full‐length P1 are too large to achieve high‐resolution data for full structural analysis by NMR. Here, we report on biologically relevant interactions of the individual C3 domain with A3VP1, a polypeptide that represents the apical head of P1 as it is projected on the cell surface. Also evaluated are C3’s interaction with C12 and the adhesion‐inhibiting monoclonal antibody (MAb) 6‐8C. NMR titration experiments with ¹⁵N‐enriched C3 demonstrate its specific binding to A3VP1. Based on resolved C3 assignments, two binding sites, proximal and distal, are identified. Complementary NMR titration of A3VP1 with a C3/C12 complex suggests that binding of A3VP1 occurs on the distal C3 binding site, while the proximal site is occupied by C12. The MAb 6‐8C binding interface to C3 overlaps with that of A3VP1 at the distal site. Together, these results identify a specific C3‐A3VP1 interaction that serves as a foundation for understanding the interaction of C123 with P1 on the bacterial surface and the related biological processes that stem from this interaction.
Database
BMRB submission code: 27935.
... Our data suggest that, like other streptococcal AgI/II family polypeptides, BspC plays a role in immune stimulation. AgI/II family proteins contain two antigenic regions (the antigens I/II and II) [69] and this ability to elicit an inflammatory response makes SpaP, the S. mutans AgI/II protein, an attractive candidate for vaccine development to prevent dental caries [14,70]. In this study we found that BspC can stimulate NF-κB activation and the release of the proinflammatory cytokines IL-8 and CXCL-1 from hCMEC. ...
Streptococcus agalactiae (Group B Streptococcus, GBS) normally colonizes healthy adults but can cause invasive disease, such as meningitis, in the newborn. To gain access to the central nervous system, GBS must interact with and penetrate brain or meningeal blood vessels; however, the exact mechanisms are still being elucidated. Here, we investigate the contribution of BspC, an antigen I/II family adhesin, to the pathogenesis of GBS meningitis. Disruption of the bspC gene reduced GBS adherence to human cerebral microvascular endothelial cells (hCMEC), while heterologous expression of BspC in non-adherent Lactococcus lactis conferred bacterial attachment. In a murine model of hematogenous meningitis, mice infected with ΔbspC mutants exhibited lower mortality as well as decreased brain bacterial counts and inflammatory infiltrate compared to mice infected with WT GBS strains. Further, BspC was both necessary and sufficient to induce neutrophil chemokine expression. We determined that BspC interacts with the host cytoskeleton component vimentin, and confirmed this interaction using a bacterial two-hybrid assay, microscale thermophoresis, immunofluorescent staining, and imaging flow cytometry. Vimentin null mice were protected from WT GBS infection and also exhibited less inflammatory cytokine production in brain tissue. These results suggest that BspC and the vimentin interaction is critical for the pathogenesis of GBS meningitis.
... Furthermore, in a recent publication, a member of the AgI/II family polypeptides, which was first identified in S. mutans [53], SpaP, has been found to be important direct interaction with C. albicans in vitro, and to facilitate colonization of both microorganisms in a D. melanogaster in vivo model [54]. ...
The human oral cavity is normally colonized by a wide range of microorganisms, including bacteria, fungi, Archaea, viruses, and protozoa. Within the different oral microenvironments these organisms are often found as part of highly organized microbial communities termed biofilms, which display consortial behavior. Formation and maintenance of these biofilms are highly dependent on the direct interactions between the different members of the microbiota, as well as on the released factors that influence the surrounding microbial populations. These complex biofilm dynamics influence oral health and disease. In the latest years there has been an increased recognition of the important role that interkingdom interactions, in particular those between fungi and bacteria, play within the oral cavity. Candida spp., and in particular C. albicans, are among the most important fungi colonizing the oral cavity of humans and have been found to participate in these complex microbial oral biofilms. C. albicans has been reported to interact with individual members of the oral bacterial microbiota, leading to either synergistic or antagonistic relationships. In this review we describe some of the better characterized interactions between Candida spp. and oral bacteria.
... [5][6][7][8] Virulence factors, including the adhesin antigens I/II (Ag I/II), glucosyltransferases, and glucan-binding protein, improve the ability of S. mutans to adhere and accumulate in the dental biofilm. 9 Numerous studies have demonstrated the importance of immunoresponse against Ag I/II in human protection against S. mutans colonization. 13 In vitro studies with Ag I/II-knockout S. mutans strains have shown decreased adhesion to hydroxyapatite on the enamel surface, suggesting that Ag I/II facilitates the adhesion of the bacteria. ...
Formation of a dental biofilm by Streptococcus mutans can cause dental caries, and remains a costly health problem worldwide. Recently, there has been a growing interest in the use of peptidic drugs, such as peptide p1025, analogous to the fragments 1025–1044 of S. mutans cellular adhesin, responsible for the adhesion and formation of dental biofilm. However, peptides have physicochemical characteristics that may affect their biological action, limiting their clinical performance. Therefore, drug-delivery systems, such as a bioadhesive liquid-crystalline system (LCS), may be attractive strategies for peptide delivery. Potentiation of the action of LCS can be achieved with the use of bioadhesive polymers to prolong their residence on the teeth. In line with this, three formulations – polyoxypropylene-(5)-polyoxyethylene-(20)-cetyl alcohol, oleic acid, and Carbopol C974P in different combinations (F1C, F2C, and F3C) were developed to observe the influence of water in the LCS, with the aim of achieving in situ gelling in the oral environment. These formulations were assessed by polarized light microscopy, small-angle X-ray scattering, rheological analysis, and in vitro bioadhesion analysis. Then, p1025 and a control (chlorhexidine) were incorporated into the aqueous phase of the formulation (F + p1025 and F + chlorhexidine), to determine their antibiofilm effect and toxicity on epithelial cells. Polarized light microscopy and small-angle X-ray scattering showed that F1C and F2C were LCS, whereas F3C was a microemulsion. F1C and F2C showed pseudoplastic behavior and F3C Newtonian behavior. F1C showed the highest elastic and bioadhesive characteristics compared to other formulations. Antibiofilm effects were observed for F + p1025 when applied in the surface-bound salivary phase. The p1025-loaded nanostructured LCS presented limited cytotoxicity and effectively reduced S. mutans biofilm formation, and could be a promising p1025-delivery strategy to prevent the formation of S. mutans dental biofilm.
... Biofilm formation by mutan streptococci, particularly Streptococcus mutans and Streptococcus sorbinus follows two pathways: sucrose dependent adherence and sucrose independent adherence. In the later route, oral streptococcal surface protein antigen (a cell wall associated adhesin P1 and a member of antigen I/II (AgI/II) encoded by spaP gene) is involved [73,69]. A 29 kDa surface protein known as wall associated protein A (WapA, antigen A or antigen III) also plays a vital structural role at the cell surface for the formation of biofilm and cell to cell interaction [70]. ...
Introduction
Dental caries is known to be one of the most widespread, chronic infections affecting all ages and populations worldwide. The plethora of oral microbial population paves way for various endogenous infections and plays a crucial role in polymicrobial interactions contributing to biofilm-mediated diseases like caries and periodontal diseases.
Methods
Extensive literature survey was conducted using the scientific databases like PubMed, Google scholar, Science Direct, etc. using the key words like dental caries, orodental infections, dental microbes, dental biofilm, secondary caries, phytotherapy, etc. The literature was analyzed thoroughly and critical review was performed.
Results
The risk of development of secondary caries and residual caries further results in treatment failure. Drug resistance developed by oral microbes and further side effects pose serious hurdles in the current therapeutic strategies. The hyperactivities of various MMPs and the resulting massive ECM degradation are the challenging part in the design of effective therapeutic approaches. Anticariogenic phytotherapy is well appreciated owing to lesser side effects and versatility of their action. But appreciable outcomes regarding the phytochemical bioavailability and bioretention are still challenging. Site-specific delivery of phytoagents at the infected site may enhance the efficiency of these drugs. Accordingly emerging phytodentistry can be promising for the management of secondary and residual caries.
Conclusion
This article presents major cariogens and their mechanisms in initiating and aggravating dental caries. Effectiveness of phytotherapy and different mode of action of phytochemicals against cariogens are outlined. The article also raises major concerns and possibilities of phytochemical based therapeutics to be applied in the clinical arena of caries management.
... In the current study, we identified S. mutans wall-associated protein A (WapA) and an uncharacterized secreted protein, SMU_63c, as capable of amyloid fibrillization. We also determined that the naturally occurring C-terminal breakdown product of P1 (C123), known originally as antigen II (AgII) [21], represents the amyloidogenic moiety of P1. Immunogold electron microscopy (EM) experiments employing specific antibodies identified all three amyloidogenic proteins within the fibrous structure of the ECM of biofilms. ...
Amyloids have been identified as functional components of the extracellular matrix of bacterial biofilms. Streptococcus mutans is an established etiologic agent of dental caries and biofilm dweller. In addition to the previously identified amyloidogenic adhesin P1 (aka AgI/II, PAc), we show that the naturally occurring Antigen A derivative of S. mutans wall-associated protein A (WapA), and the secreted protein SMU_63c, can also form amyloid fibrils. P1, WapA and SMU_63c were found to significantly influence biofilm development and architecture, and all three proteins were shown by immunogold electron microscopy to reside within fibrillar extracellular matrix of the biofilms. We also showed that SMU_63c functions as a negative regulator of biofilm cell density and genetic competence. In addition, the naturally occurring C-terminal cleavage product of P1, C123 (aka AgII), was shown to represent the amyloidogenic moiety of this protein. Thus, P1 and WapA both represent sortase substrates that are processed to amyloidogenic truncation derivatives. Our current results suggest a novel mechanism by which certain cell surface adhesins are processed and contribute to the amyloidogenic capability of S. mutans. We further demonstrate that the polyphenolic small molecules tannic acid and epigallocatechin-3-gallate (EGCG), and the benzoquinone derivative AA-861, which all inhibit amyloid fibrillization of C123 and AgA in vitro, also inhibit S. mutans biofilm formation via P1 and WapA-dependent mechanisms, indicating that these proteins serve as therapeutic targets of anti-amyloid compounds.
