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Streptococcal M protein: molecular design and biological behavior

V A Fischetti1

  • 1Rockefeller University, New York, New York 10021.

Clinical Microbiology Reviews
|July 1, 1989
PubMed

Insights

Group A Streptococcus M protein, a key virulence factor, uses a coiled-coil structure for immune evasion and antigenic variation. This structure

Area of Science:

  • Microbiology
  • Structural Biology
  • Immunology

Background:

  • Group A Streptococcus (GAS) M protein is a critical virulence factor enabling bacterial resistance to phagocytosis.
  • The M protein's structure, characterized by a fibrillar coiled-coil design, is common in eukaryotic proteins and may be a conserved motif in Gram-positive bacteria.

Purpose of the Study:

  • To elucidate the structural basis of M protein's virulence.
  • To explore the implications of its coiled-coil structure for bacterial survival and host interactions.
  • To investigate the molecular basis of serological cross-reactions between microbial and mammalian proteins.

Main Methods:

  • Structural analysis of the M protein.
  • Investigation of functional domains and antigenic properties.
  • Comparative molecular design analysis with mammalian proteins.

Main Results:

  • The coiled-coil structure of M protein provides advantages such as antigenic variation and multiple functional domains.
  • Structural similarities between M protein and mammalian proteins may explain observed serological cross-reactions.
  • The elucidated structural features offer insights into M protein's role in virulence.

Conclusions:

  • The fibrillar coiled-coil structure is a significant feature of M protein, contributing to its role as a major virulence determinant.
  • Understanding M protein structure aids in explaining host-pathogen interactions and serological cross-reactivity.
  • The methodologies used can be applied to study similar surface proteins in other microbial systems.

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