Advanced

Molecular characterization of protein Sir, a streptococcal cell surface protein that binds both immunoglobulin A and immunoglobulin G

Stenberg, Lars LU ; O'Toole, P W; Mestecky, J and Lindahl, Gunnar LU (1994) In Journal of Biological Chemistry 269(18). p.13458-13464
Abstract
Cell surface proteins that bind to the Fc part of immunoglobulin (Ig) A and/or IgG are expressed by many strains of the group A Streptococcus, an important human pathogen. Two extensively characterized proteins in this group of molecules are protein Arp that preferentially binds IgA and protein H that binds IgG. In addition, recent work has shown that many group A streptococcal strains express a novel type of Fc-binding protein, designated protein Sir, that binds both IgA and IgG. Protein Sir22, the molecule expressed by a strain of serotype M22, has now been purified and characterized after expression of the cloned gene in Escherichia coli. Dot-blot analysis with a large number of purified monoclonal Igs showed that protein Sir22 reacted... (More)
Cell surface proteins that bind to the Fc part of immunoglobulin (Ig) A and/or IgG are expressed by many strains of the group A Streptococcus, an important human pathogen. Two extensively characterized proteins in this group of molecules are protein Arp that preferentially binds IgA and protein H that binds IgG. In addition, recent work has shown that many group A streptococcal strains express a novel type of Fc-binding protein, designated protein Sir, that binds both IgA and IgG. Protein Sir22, the molecule expressed by a strain of serotype M22, has now been purified and characterized after expression of the cloned gene in Escherichia coli. Dot-blot analysis with a large number of purified monoclonal Igs showed that protein Sir22 reacted with 19 out of 20 IgA proteins and with 19 out of 24 IgG proteins. The affinity constants for the reactions between protein Sir22 and Ig were determined to be 7.0 x 10(8) M-1 for serum IgA, 2.4 x 10(8 M-1 for secretory IgA, and 7.8 x 10(8) M-1 for IgG. Inhibition experiments showed that the bindings of IgA and IgG to protein Sir22 were mutually exclusive, indicating shared or contiguous binding sites. Analysis of the sequence of the sir22 gene indicated a gene product with 365 amino acid residues, including a 41-residue signal peptide. The processed form of the protein, 324 residues, has a calculated M(r) of 37,168. Deletion analysis of the sir22 gene showed that a 156-residue NH2-terminal fragment of protein Sir22 retained the ability to bind both IgA and IgG. The overall organization of protein Sir22 is similar to that of the IgA-binding protein Arp and the IgG-binding protein H. All three of these proteins are members of the M protein family and have a central repeat region of the C type. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Biological Chemistry
volume
269
issue
18
pages
13458 - 13464
publisher
ASBMB
external identifiers
  • pmid:8175778
  • scopus:0028225870
ISSN
1083-351X
language
English
LU publication?
yes
id
e42b4b75-aca6-4d26-b74e-8d8c8b2e5134 (old id 1107967)
alternative location
http://www.jbc.org/cgi/reprint/269/18/13458
date added to LUP
2008-07-23 10:31:44
date last changed
2017-08-20 03:41:51
@article{e42b4b75-aca6-4d26-b74e-8d8c8b2e5134,
  abstract     = {Cell surface proteins that bind to the Fc part of immunoglobulin (Ig) A and/or IgG are expressed by many strains of the group A Streptococcus, an important human pathogen. Two extensively characterized proteins in this group of molecules are protein Arp that preferentially binds IgA and protein H that binds IgG. In addition, recent work has shown that many group A streptococcal strains express a novel type of Fc-binding protein, designated protein Sir, that binds both IgA and IgG. Protein Sir22, the molecule expressed by a strain of serotype M22, has now been purified and characterized after expression of the cloned gene in Escherichia coli. Dot-blot analysis with a large number of purified monoclonal Igs showed that protein Sir22 reacted with 19 out of 20 IgA proteins and with 19 out of 24 IgG proteins. The affinity constants for the reactions between protein Sir22 and Ig were determined to be 7.0 x 10(8) M-1 for serum IgA, 2.4 x 10(8 M-1 for secretory IgA, and 7.8 x 10(8) M-1 for IgG. Inhibition experiments showed that the bindings of IgA and IgG to protein Sir22 were mutually exclusive, indicating shared or contiguous binding sites. Analysis of the sequence of the sir22 gene indicated a gene product with 365 amino acid residues, including a 41-residue signal peptide. The processed form of the protein, 324 residues, has a calculated M(r) of 37,168. Deletion analysis of the sir22 gene showed that a 156-residue NH2-terminal fragment of protein Sir22 retained the ability to bind both IgA and IgG. The overall organization of protein Sir22 is similar to that of the IgA-binding protein Arp and the IgG-binding protein H. All three of these proteins are members of the M protein family and have a central repeat region of the C type.},
  author       = {Stenberg, Lars and O'Toole, P W and Mestecky, J and Lindahl, Gunnar},
  issn         = {1083-351X},
  language     = {eng},
  number       = {18},
  pages        = {13458--13464},
  publisher    = {ASBMB},
  series       = {Journal of Biological Chemistry},
  title        = {Molecular characterization of protein Sir, a streptococcal cell surface protein that binds both immunoglobulin A and immunoglobulin G},
  volume       = {269},
  year         = {1994},
}