M protein (Streptococcus): Difference between revisions
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'''M protein''' is a [[virulence factor]] that can be produced by certain species of ''[[Streptococcus]]''.<ref name="pmid10846214">{{cite journal |vauthors=Chanter N, Talbot NC, Newton JR, Hewson D, Verheyen K |title=Streptococcus equi with truncated M-proteins isolated from outwardly healthy horses |journal=Microbiology |issue= Pt 6 |pages=1361–9 |volume=146 |date=June 2000 |pmid=10846214 |doi= 10.1099/00221287-146-6-1361|url=http://mic.sgmjournals.org/cgi/pmidlookup?view=long&pmid=10846214|doi-access=free }}</ref> |
'''M protein''' is a [[virulence factor]] that can be produced by certain species of ''[[Streptococcus]]''.<ref name="pmid10846214">{{cite journal |vauthors=Chanter N, Talbot NC, Newton JR, Hewson D, Verheyen K |title=Streptococcus equi with truncated M-proteins isolated from outwardly healthy horses |journal=Microbiology |issue= Pt 6 |pages=1361–9 |volume=146 |date=June 2000 |pmid=10846214 |doi= 10.1099/00221287-146-6-1361|url=http://mic.sgmjournals.org/cgi/pmidlookup?view=long&pmid=10846214|doi-access=free }}</ref> |
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Viruses, [[parasite]]s and [[Zinc dependent phospholipase C|bacteria]] are covered in [[protein]] and [[sugar]] [[molecule]]s that help them gain entry into a host by counteracting the host's defenses. One such molecule is the M protein produced by certain streptococcal [[bacterium|bacteria]]. At its C-terminus within the cell wall, M [[protein]]s embody a [[protein motif|motif]] that is now known to be shared by many [[Gram-positive]] [[bacteria]]l surface [[proteins]]. The [[sequence motif|motif]] includes a [[conserved sequence|conserved]] |
Viruses, [[parasite]]s and [[Zinc dependent phospholipase C|bacteria]] are covered in [[protein]] and [[sugar]] [[molecule]]s that help them gain entry into a host by counteracting the host's defenses. One such molecule is the M protein produced by certain streptococcal [[bacterium|bacteria]]. At its C-terminus within the cell wall, M [[protein]]s embody a [[protein motif|motif]] that is now known to be shared by many [[Gram-positive]] [[bacteria]]l surface [[proteins]]. The [[sequence motif|motif]] includes a [[conserved sequence|conserved]] hexapeptide LPXTGE, which precedes a [[hydrophobic]] C-terminal [[Cell membrane|membrane]] spanning domain, which itself precedes a cluster of [[Base (chemistry)|basic]] [[residue (chemistry)|residues]] at the C-terminus.<ref name="pmid2188957">{{cite journal |vauthors=Schneewind O, Jones KF, Fischetti VA | title = Sequence and structural characteristics of the trypsin-resistant T6 surface protein of group A streptococci | journal = J. Bacteriol. | volume = 172 | issue = 6 | pages = 3310–7 |date=June 1990 | pmid = 2188957 | pmc = 209141 }}</ref><ref name="pmid2287281">{{cite journal |vauthors=Fischetti VA, Pancholi V, Schneewind O | title = Conservation of a pentapeptide sequence in the anchor region of surface proteins from gram-positive cocci | journal = Mol. Microbiol. | volume = 4 | issue = 9 | pages = 1603–5 |date=September 1990 | pmid = 2287281 | doi = 10.1111/j.1365-2958.1990.tb02072.x}}</ref> |
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M protein is strongly anti-phagocytic and is the major virulence factor for group A streptococci (''Streptococcus pyogenes''). It binds to serum [[factor H]], destroying [[C3-convertase]] and preventing [[opsonization]] by [[C3b]]. However plasma B cells can generate antibodies against M protein which will help in opsonization and further the destruction of the microorganism by the macrophages and neutrophils. [[Cross-reactivity]] of anti-M protein antibodies with heart muscle has been suggested to be associated in some way with [[rheumatic fever]]. |
M protein is strongly anti-phagocytic and is the major virulence factor for group A streptococci (''Streptococcus pyogenes''). It binds to serum [[factor H]], destroying [[C3-convertase]] and preventing [[opsonization]] by [[C3b]]. However plasma B cells can generate antibodies against M protein which will help in opsonization and further the destruction of the microorganism by the macrophages and neutrophils. [[Cross-reactivity]] of anti-M protein antibodies with heart muscle has been suggested to be associated in some way with [[rheumatic fever]]. |
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Revision as of 14:06, 6 February 2023
| Gram_pos_anchor | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| Symbol | Gram_pos_anchor | ||||||||
| Pfam | PF00746 | ||||||||
| Pfam clan | CL0501 | ||||||||
| InterPro | IPR019948 | ||||||||
| PROSITE | PDOC00373 | ||||||||
| |||||||||
M protein is a virulence factor that can be produced by certain species of Streptococcus.[1]
Viruses, parasites and bacteria are covered in protein and sugar molecules that help them gain entry into a host by counteracting the host's defenses. One such molecule is the M protein produced by certain streptococcal bacteria. At its C-terminus within the cell wall, M proteins embody a motif that is now known to be shared by many Gram-positive bacterial surface proteins. The motif includes a conserved hexapeptide LPXTGE, which precedes a hydrophobic C-terminal membrane spanning domain, which itself precedes a cluster of basic residues at the C-terminus.[2][3]
M protein is strongly anti-phagocytic and is the major virulence factor for group A streptococci (Streptococcus pyogenes). It binds to serum factor H, destroying C3-convertase and preventing opsonization by C3b. However plasma B cells can generate antibodies against M protein which will help in opsonization and further the destruction of the microorganism by the macrophages and neutrophils. Cross-reactivity of anti-M protein antibodies with heart muscle has been suggested to be associated in some way with rheumatic fever.
It was originally identified by Rebecca Lancefield,[4] who also formulated the Lancefield classification system for streptococcal bacteria. Bacteria like S. pyogenes, which possess M protein are classified in group A of the Lancefield system.
Literature
- Fischetti VA, Pancholi V, Schneewind O (September 1990). "Conservation of a hexapeptide sequence in the anchor region of surface proteins from gram-positive cocci". Mol. Microbiol. 4 (9): 1603–5. doi:10.1111/j.1365-2958.1990.tb02072.x. PMID 2287281.
- Pierre R. Smeesters; David J. McMillan; Kadaba S. Sriprakash (June 2010). "The streptococcal M protein: a highly versatile molecule". Trends in Microbiology. 18 (6): 275–282. doi:10.1016/j.tim.2010.02.007. PMID 20347595.
References
- ^ Chanter N, Talbot NC, Newton JR, Hewson D, Verheyen K (June 2000). "Streptococcus equi with truncated M-proteins isolated from outwardly healthy horses". Microbiology. 146 (Pt 6): 1361–9. doi:10.1099/00221287-146-6-1361. PMID 10846214.
- ^ Schneewind O, Jones KF, Fischetti VA (June 1990). "Sequence and structural characteristics of the trypsin-resistant T6 surface protein of group A streptococci". J. Bacteriol. 172 (6): 3310–7. PMC 209141. PMID 2188957.
- ^ Fischetti VA, Pancholi V, Schneewind O (September 1990). "Conservation of a pentapeptide sequence in the anchor region of surface proteins from gram-positive cocci". Mol. Microbiol. 4 (9): 1603–5. doi:10.1111/j.1365-2958.1990.tb02072.x. PMID 2287281.
- ^ "Streptococcal M protein: molecular design and biological behavior". Retrieved 2009-06-21.