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Extensive sequence homology between IgA receptor and M proteins in Streptococcus pyogenes
Author(s) -
Frithz E.,
Hedén L.O.,
Lindahl G.
Publication year - 1989
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1989.tb00261.x
Subject(s) - biology , peptide sequence , streptococcus pyogenes , homology (biology) , nucleic acid sequence , biochemistry , periplasmic space , microbiology and biotechnology , amino acid , gene , genetics , escherichia coli , bacteria , staphylococcus aureus
Summary Many strains of Streptococcus pyogenes are known to express a receptor for IgA. The complete nucleotide sequence of the gene for such a receptor, protein Arp4, has been determined. The deduced amino acid sequence of 386 residues includes a signal sequence of 41 amino acids and a putative membrane anchor region, both of which are homologous to similar regions in other streptococcal surface proteins. The processed form of the IgA receptor has a length of 345 amino acids and a calculated molecular weight of 39544. The N‐terninal sequence of the processed form is different from that previously found for a similar IgA receptor isolated from a S. pyogenes strain of type M60. The sequence of protein Arp4 shows extensive homology to the C ‐terminal half of streptococcal M proteins, but not to the streptococcal IgG receptor protein G or staphlyococcal protein A. Apart from the membrane anchor, this homology includes a sequence of 119 amino acid residues containing three repeated units and a 54‐residue sequence without repeats. The protein expressed in Escherichia coli is found in the periplasmic space, in which it constitutes the major protein. Protein Arp4 is the first example of a surface protein that has both immunoglobulin‐binding capacity and structural features characteristic of M proteins. And structural features characteristic of MJ proteins.