scholarly journals Antigenic domains of the streptococcal Pep M5 protein. Localization of epitopes crossreactive with type 6 M protein and identification of a hypervariable region of the M molecule.

1986 ◽  
Vol 163 (1) ◽  
pp. 129-138 ◽  
Author(s):  
B N Manjula ◽  
A S Acharya ◽  
T Fairwell ◽  
V A Fischetti
Keyword(s):  
Protein Localization ◽  
Hypervariable Region ◽  
Coiled Coil ◽  
M Protein ◽  
Terminal Domain ◽  
Coil Structure ◽  
M Proteins ◽  
Group A ◽  
Antigenic Domains ◽  
Antigenic Epitopes

Pep M5, the pepsin-derived N-terminal half of the group A streptococcal type 5 M protein exhibits immunologic crossreaction with type 6 M protein, localizing some of the M6-crossreactive epitope(s) within this segment of the M5 protein. Based on the amino acid sequence of the Pep M5 protein, two structurally distinct domains have been recognized within its coiled-coil structure. We have now found that peptides derived from both the structurally distinct domains of the Pep M5 protein contain antigenic epitopes. Furthermore, only the peptides from the C-terminal domain of the Pep M5 protein crossreacted with rabbit anti-M6 sera, whereas those from the N-terminal domain did not. Consistent with this, sequence analyses of the arginyl peptides of the Pep M6 protein, the pepsin-derived N-terminal half of the M6 protein, revealed extensive homology of some of these peptides with regions within the C-terminal domain of the Pep M5 molecule. While an arginyl peptide of the Pep M6 protein exhibits 84% homology with region 150-186 of the Pep M5 protein, the C-terminal hexadecapeptide of the Pep M6 protein is virtually identical with the corresponding region of the Pep M5 protein. These results are suggestive of conformational similarities in the region around the pepsin-susceptible site within the M5 and M6 proteins. In addition, one or more epitopes of the M5 protein that are crossreactive with the M6 protein may be placed close to the pepsin-susceptible site of the M5 protein. Previous studies have suggested the N-terminal half of the M proteins to be the variable part of the molecule among the different M protein serotypes. The present results suggest that the N-terminal quarter of the M protein may represent the hypervariable domain of the M molecule.

scholarly journals Structure-based group A streptococcal vaccine design: Helical wheel homology predicts antibody cross-reactivity among streptococcal M protein–derived peptides

2020 ◽  
Vol 295 (12) ◽  
pp. 3826-3836 ◽  
Author(s):  
Michelle P. Aranha ◽  
Thomas A. Penfound ◽  
Jay A. Spencer ◽  
Rupesh Agarwal ◽  
Jerome Baudry ◽  
...  
Keyword(s):  
Group A Streptococcus ◽  
Coiled Coil ◽  
Cross Reactivity ◽  
M Protein ◽  
High Sequence Identity ◽  
Sequence Identity ◽  
Streptococcal M Protein ◽  
Helical Wheel ◽  
Group A ◽  
Immunological Assays

Group A streptococcus (Strep A) surface M protein, an α-helical coiled-coil dimer, is a vaccine target and a major determinant of streptococcal virulence. The sequence-variable N-terminal region of the M protein defines the M type and also contains epitopes that promote opsonophagocytic killing of streptococci. Recent reports have reported considerable cross-reactivity among different M types, suggesting the prospect of identifying cross-protective epitopes that would constitute a broadly protective multivalent vaccine against Strep A isolates. Here, we have used a combination of immunological assays, structural biology, and cheminformatics to construct a recombinant M protein–based vaccine that included six Strep A M peptides that were predicted to elicit antisera that would cross-react with an additional 15 nonvaccine M types of Strep A. Rabbit antisera against this recombinant vaccine cross-reacted with 10 of the 15 nonvaccine M peptides. Two of the five nonvaccine M peptides that did not cross-react shared high sequence identity (≥50%) with the vaccine peptides, implying that high sequence identity alone was insufficient for cross-reactivity among the M peptides. Additional structural analyses revealed that the sequence identity at corresponding polar helical-wheel heptad sites between vaccine and nonvaccine peptides accurately distinguishes cross-reactive from non–cross-reactive peptides. On the basis of these observations, we developed a scoring algorithm based on the sequence identity at polar heptad sites. When applied to all epidemiologically important M types, this algorithm should enable the selection of a minimal number of M peptide–based vaccine candidates that elicit broadly protective immunity against Strep A.

scholarly journals Binding of the kringle-2 domain of human plasminogen to streptococcal PAM-type M-protein causes dissociation of PAM dimers

2021 ◽  
Author(s):  
Olawole Ayinuola ◽  
Yetunde Ayinuola ◽  
Cunjia Qiu ◽  
Shaun Lee ◽  
Victoria Ploplis ◽  
...  
Keyword(s):  
Group A Streptococcus ◽  
Tight Binding ◽  
Coiled Coil ◽  
M Protein ◽  
Temperature Dependent ◽  
Functional Monomers ◽  
Molecular Weights ◽  
Group A ◽  
Human Plasminogen ◽  
Kringle 2

M-protein (PAM) largely contributes to the pathogenesis of Pattern D Group A Streptococcus pyogenes (GAS). However, the mechanism of complex formation is unknown. In a system consisting of a Class II PAM from Pattern D GAS isolate NS88.2 (PAMNS88.2), with one K2hPg binding a-repeat in its A-domain, we employed biophysical techniques to analyze the mechanism of the K2hPg/PAMNS88.2 interaction. We show that apo-PAMNS88.2 is a coiled-coil homodimer (M.Wt. ~80 kDa) at 4°C - 25°C, and is monomeric (M.Wt. ~40 kDa) at 37°C, demonstrating a temperature-dependent dissociation of PAMNS88.2 over a narrow temperature range. PAMNS88.2 displayed a single tight binding site for K2hPg at 4°C, which progressively increased at 25°C through 37°C. We isolated the K2hPg/PAMNS88.2 complexes at 4°C, 25°C, and 37°C and found molecular weights of ~50 kDa at each temperature, corresponding to a 1:1 (m:m) K2hPg/PAMNS88.2 monomer complex. hPg activation experiments by streptokinase demonstrated that the hPg/PAMNS88.2 monomer complexes are fully functional. The data show that PAM dimers dissociate into functional monomers at physiological temperatures or when presented with the active hPg module (K2hPg) showing that PAM is a functional monomer at 37°C.

scholarly journals Sequence of myosin-crossreactive epitopes of streptococcal M protein.

1986 ◽  
Vol 164 (5) ◽  
pp. 1785-1790 ◽  
Author(s):  
J B Dale ◽  
E H Beachey
Keyword(s):  
Synthetic Peptide ◽  
Synthetic Peptides ◽  
Human Myocardium ◽  
M Protein ◽  
Cardiac Myosin ◽  
Streptococcal M Protein ◽  
M Proteins ◽  
Group A ◽  
Inhibition Studies ◽  
Rheumatic Heart

Group A streptococcal M proteins contain epitopes that crossreact with sarcolemmal membrane proteins of human myocardium and myosin. In the present study, synthetic peptide copies spanning the entire 197-residue pepsin extracted fragment of type 5 M protein were used to localize the myosin-crossreactive epitopes of the molecule. Peptide 84-116 inhibited by 75% the binding of myosin-crossreactive antibodies evoked by pep M5, as determined by ELISA. Immunoblot inhibition studies confirmed that peptide 84-116 almost totally inhibited the binding of pep M5 antibodies to the heavy chain of human cardiac myosin. None of the remaining synthetic peptides, including peptide 1-35, which contains protective epitopes, inhibited antibodies binding to myosin. Two of three rabbits immunized with peptide 84-116 developed low but significant levels of antibodies crossreactive with myosin. Identification of the primary structures containing tissue-crossreactive as opposed to protective epitopes should not only allow the development of safe and effective M protein vaccines, but may also provide insights into the pathogenesis of rheumatic heart disease.

scholarly journals gpwac of the T4-Type Bacteriophages: Structure, Function, and Evolution of a Segmented Coiled-Coil Protein That Controls Viral Infectivity

2005 ◽  
Vol 187 (3) ◽  
pp. 1055-1066 ◽  
Author(s):  
A. Letarov ◽  
X. Manival ◽  
C. Desplats ◽  
H. M. Krisch
Keyword(s):  
Bacteriophage T4 ◽  
Coiled Coil ◽  
Unknown Origin ◽  
Direct Consequence ◽  
Protein Protein Interaction ◽  
Terminal Domain ◽  
C Terminus ◽  
Coil Structure ◽  
Type Phage ◽  
Gene Orthologs

ABSTRACT The wac gene product (gpwac) or fibritin of bacteriophage T4 forms the six fibers that radiate from the phage neck. During phage morphogenesis these whiskers bind the long tail fibers (LTFs) and facilitate their attachment to the phage baseplate. After the cell lysis, the gpwac fibers function as part of an environmental sensing device that retains the LTFs in a retracted configuration and thus prevents phage adsorption in unfavorable conditions. A comparative analysis of the sequences of 5 wac gene orthologs from various T4-type phages reveals that the ∼50-amino-acid N-terminal domain is the only highly conserved segment of the protein. This sequence conservation is probably a direct consequence of the domain's strong and specific interactions with the neck proteins. The sequence of the central fibrous region of gpwac is highly plastic, with only the heptad periodicity of the coiled-coil structure being conserved. In the various gpwac sequences, the small C-terminal domain essential for initiation of the folding of T4 gpwac is replaced by unrelated sequences of unknown origin. When a distant T4-type phage has a novel C-terminal gpwac sequence, the phage's gp36 sequence that is located at the knee joint of the LTF invariably has a novel domain in its C terminus as well. The covariance of these two sequences is compatible with genetic data suggesting that the C termini of gpwac and gp36 engage in a protein-protein interaction that controls phage infectivity. These results add to the limited evidence for domain swapping in the evolution of phage structural proteins.

scholarly journals Opsonic antibodies evoked by hybrid peptide copies of types 5 and 24 streptococcal M proteins synthesized in tandem.

1986 ◽  
Vol 163 (6) ◽  
pp. 1451-1458 ◽  
Author(s):  
E H Beachey ◽  
H Gras-Masse ◽  
A Tarter ◽  
M Jolivet ◽  
F Audibert ◽  
...  
Keyword(s):  
Heart Tissue ◽  
M Protein ◽  
Amino Terminus ◽  
Infectious Agents ◽  
Hybrid Peptide ◽  
New Approach ◽  
Hybrid Peptides ◽  
M Proteins ◽  
Group A ◽  
Carboxy Terminal

The protective immunogenicity of a hybrid peptide containing tandem copies of types 5 and 24 epitopes was investigated. Carboxy-terminal peptides of the cyanogen bromide-derived fragment 7 (CB7) of type 24 M protein were chemically synthesized, and then extended to include the first 20 residues of the amino-terminus of type 5 M protein. When emulsified in CFA and injected into rabbits without conjugation to a carrier, each of the synthetic hybrid peptides, designated S-M5(1-20)-S-CB7(23-35)C and S-M5(1-20)-S-CB(19-34), evoked opsonic antibodies against both types 5 and 24 streptococci without raising heart tissue-crossreactive immunity. These results suggest that tandem hybrid peptides may provide a new approach to the development of multivalent vaccines, not only to different serotypes of group A streptococci but perhaps also to a variety of other infectious agents.

scholarly journals Difference in the structural features of streptococcal M proteins from nephritogenic and rheumatogenic serotypes.

1987 ◽  
Vol 166 (1) ◽  
pp. 151-162 ◽  
Author(s):  
K M Khandke ◽  
T Fairwell ◽  
B N Manjula
Keyword(s):  
Tertiary Structure ◽  
Structural Information ◽  
Gel Filtration ◽  
Structural Features ◽  
Biologically Active ◽  
M Protein ◽  
Acute Glomerulonephritis ◽  
Group A Streptococci ◽  
M Proteins ◽  
Group A

The association of only certain M protein serotypes of group A streptococci with acute glomerulonephritis is very well recognized. Structural information on the M protein, a dimeric alpha-helical coiled-coil molecule, has come so far from three rheumatogenic serotypes, 5, 6, and 24. However, M proteins from the nephritogenic serotypes have not been well characterized. In the present study, we have isolated a biologically active 20,000 Mr pepsin fragment of type 49 M protein (PepM49), a nephritogenic serotype, and purified it to homogeneity using DEAE-Sephadex and gel filtration. The amino acid composition of PepM49 is similar to those of the rheumatogenic M protein serotypes PepM5, PepM6, and PepM24. However, the sequence of the NH2-terminal 60 residues of PepM49 shows little homology to any of these M protein serotypes, although the latter have significant homology among themselves. Nevertheless, PepM49 exhibits a strong heptad periodicity in its nonpolar residues, suggesting its overall conformational similarity with the other M molecules. During the course of the present studies, Moravek et al. (17) reported the NH2-terminal sequence of another M protein serotype, PepM1, which also does not exhibit much homology with the PepM5, PepM6, and PepM24 proteins. Our analysis of this sequence revealed that the PepM1 protein also exhibits a heptad periodicity of the nonpolar amino acids. A closer examination has revealed that the pattern of heptad periodicity in PepM49 and PepM1 proteins is more regular and more similar to each other than has been previously seen for the PepM5, PepM6, and PepM24 proteins. PepM1 is also a nephritogenic serotype. Taken together, these findings indicate an underlying conservation of the tertiary structure of the various M protein serotypes, despite the complexity in their antigenic variation and suggest that the nephritogenic M protein serotypes M1 and M49 may be further apart evolutionarily from the rheumatogenic serotypes 5, 6, and 24. The distinct differences in the structural features of the PepM1 and PepM49 proteins relative to the PepM5, PepM6, and PepM24 proteins are also suggestive of a correlation with the earlier broader classification of the group A streptococci into rheumatogenic and nephritogenic serotypes.

scholarly journals Identification and Characterization of a Novel Secreted Immunoglobulin Binding Protein from Group A Streptococcus

2001 ◽  
Vol 69 (8) ◽  
pp. 4851-4857 ◽  
Author(s):  
Peter K. Fagan ◽  
Dieter Reinscheid ◽  
Birgit Gottschalk ◽  
Gursharan S. Chhatwal
Keyword(s):  
Binding Proteins ◽  
Group A Streptococcus ◽  
Binding Protein ◽  
Coiled Coil ◽  
Invasive Disease ◽  
Local Similarity ◽  
M Proteins ◽  
Immunoglobulin Binding Protein ◽  
Group A ◽  
Immunoglobulin Binding

ABSTRACT Immunoglobulin binding proteins are one of several pathogenicity factors which have been associated with invasive disease caused by group A streptococci. The surface-bound M and M-like proteins ofStreptococcus pyogenes are the most characterized of these immunoglobulin binding proteins, and in most cases they bind only a single antibody class. Here we report the identification of a novel non-M-type secreted protein, designated SibA (for secreted immunoglobulin binding protein from group A streptococcus), which binds all immunoglobulin G (IgG) subclasses, the Fc and Fab fragments, and also IgA and IgM. SibA has no significant sequence homology to any M-related proteins, is not found in the vir regulon, and contains none of the characteristic M-protein regions, such as the A or C repeats. Like M proteins, however, SibA does have relatively high levels of alanine, lysine, glutamic acid, leucine, and glycine. SibA and M proteins also share an alpha-helical N-terminal secondary structure which has been previously implicated in immunoglobulin binding in M proteins. Evidence presented here indicates that this is also the case for SibA. SibA also has regions of local similarity with other coiled-coil proteins such as Listeria monocytogenes P45 autolysin, human myosin heavy chain, macrogolgin, and Schistoma mansoni paramyosin, some of which are of potential significance since cross-reactive antibodies between myosin proteins and M proteins have been implicated in the development of the autoimmune sequelae of streptococcal disease.

scholarly journals Multivalent Group A Streptococcal Vaccine Elicits Bactericidal Antibodies against Variant M Subtypes

2005 ◽  
Vol 12 (7) ◽  
pp. 833-836 ◽  
Author(s):  
James B. Dale ◽  
Thomas Penfound ◽  
Edna Y. Chiang ◽  
Valerie Long ◽  
Stanford T. Shulman ◽  
...  
Keyword(s):  
Wide Spectrum ◽  
Epidemiologic Studies ◽  
M Protein ◽  
Group A Streptococci ◽  
Protein Vaccine ◽  
Amino Terminal ◽  
M Proteins ◽  
Group A ◽  
Clinical Illness

ABSTRACT Group A streptococci cause a wide spectrum of clinical illness. One of several strategies for vaccine prevention of these infections is based on the type-specific M protein epitopes. A multivalent M protein-based vaccine containing type-specific determinants from 26 different M serotypes is now in clinical trials. Recent epidemiologic studies have shown that, within some serotypes, the amino-terminal M protein sequence may show natural variation, giving rise to subtypes. This raises the possibility that vaccine-induced antibodies against the parent type may not be as effective in promoting bactericidal killing of variant subtypes. In the present study we used rabbit antisera against the 26-valent M protein-based vaccine in bactericidal tests against M1, M3, and M5 streptococci, which were represented by multiple subtypes. We show that the vaccine antibodies effectively promoted in vitro bactericidal activity despite the fact that the M proteins contained naturally occurring variant sequences in the regions corresponding to the vaccine sequence. Our results show that the variant M proteins generally do not result in significant differences in opsonization promoted by rabbit antisera raised against the 26-valent vaccine, suggesting that a multivalent M protein vaccine may not permit variant subtypes of group A streptococci to escape in a highly immunized population.

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