title: Immunoglobulin-binding FcrA and Enn proteins and M proteins of group A streptococci evolved independently from a common ancestral protein.
abstract: Significant sequence homology between M proteins and immunoglobulin (Ig)-binding proteins of group A streptococci suggests that these proteins arose by gene duplication followed by the development of functional diversity due to mutations and intragenic recombinations. The deduced sequence of multiple Ig-binding proteins and M proteins were compared to distinguish between two evolutionary models. Did these functionally distinct genes originate in the distant past from duplication of a common ancestral gene and then functionally evolve independently or did they evolve more recently, one from the other by duplication of a fixed gene? Multiple alignments of conserved sequences of these proteins are consistent with the former hypothesis. Comparison of N termini of Ig-binding proteins revealed less diversity than that of the M proteins' N termini, suggesting that these proteins are under less selective pressure to change.
authors.affiliation: Department of Medical Microbiology, Hospital of the Technical University, Aachen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Podbielski
authors.forename: J
authors.initials: J
authors.lastname: Weber-Heynemann
authors.forename: P P
authors.initials: PP
authors.lastname: Cleary
mesh_terms: D000595:Amino Acid Sequence; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000235:genetics*; D005075:Biological Evolution; D002352:Carrier Proteins; D005796:Genes; D008222:Lymphokines / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D029584:Prostatic Secretory Proteins; D017386:Sequence Homology, Amino Acid; D013297:Streptococcus pyogenes / Q000235:genetics*
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D008222:Lymphokines; D029584:Prostatic Secretory Proteins; C043076:beta-microseminoprotein; C013059:immunoglobulin-binding factors; C014689:streptococcal M protein