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Title: SpyB, a small heme-binding protein, affects the composition of the cell wall in Streptococcus pyogenes

Streptococcus pyogenes (Group A Streptococcus or GAS) is a hemolytic human pathogen associated with a wide variety of infections ranging from minor skin and throat infections to life-threatening invasive diseases. The cell wall of GAS consists of peptidoglycan sacculus decorated with a carbohydrate comprising a polyrhamnose backbone with immunodominant N-acetylglucosamine side-chains. All GAS genomes contain the spyBA operon, which encodes a 35-amino-acid membrane protein SpyB, and a membrane-bound C 3-like ADP-ribosyltransferase SpyA. In this study, we addressed the function of SpyB in GAS. Phenotypic analysis of a spyB deletion mutant revealed increased bacterial aggregation, and reduced sensitivity to β-lactams of the cephalosporin class and peptidoglycan hydrolase PlyC. Glycosyl composition analysis of cell wall isolated from the spyB mutant suggested an altered carbohydrate structure compared with the wild-type strain. Furthermore, we found that SpyB associates with heme and protoporphyrin IX. Heme binding induces SpyB dimerization, which involves disulfide bond formation between the subunits. Furthermore, our data suggest the possibility that SpyB activity is regulated by heme.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [1] ;  [4] ;  [4] ;  [4] ;  [3] ;  [3] ;  [1] ;  [1] ;  [2] ;  [1]
  1. Univ. of Kentucky, Lexington, KY (United States)
  2. The Ohio State Univ., Columbus, OH (United States)
  3. Univ. of Washington, Seattle, WA (United States)
  4. Univ. of Georgia, Athens, GA (United States)
Publication Date:
Grant/Contract Number:
FG02-93ER20097
Type:
Accepted Manuscript
Journal Name:
Frontiers in Cellular and Infection Microbiology
Additional Journal Information:
Journal Volume: 6; Journal ID: ISSN 2235-2988
Publisher:
Frontiers Research Foundation
Research Org:
University of Georgia Research Foundation, Inc., Athens, GA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 59 BASIC BIOLOGICAL SCIENCES; SpyA; SpyB; heme; ADP-ribosyltransferase; Group A carbohydrate; Streptococcus pyogenes; cell wall
OSTI Identifier:
1365842