Identification of the Actin and Plasminogen Binding Regions of Group B Streptococcal Phosphoglycerate Kinase

Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada.
Journal of Biological Chemistry (Impact Factor: 4.57). 07/2012; 287(34):29035-44. DOI: 10.1074/jbc.M112.361261
Source: PubMed


Phosphoglycerate kinase (PGK), present on the surface of group B streptococcus (GBS), has previously been demonstrated to bind the host proteins actin and plasminogen. The actin and plasminogen binding sites of GBS-PGK were identified using truncated GBS-PGK molecules, followed by peptide mapping. These experiments identified two actin and plasminogen binding sites located between amino acids 126-134 and 204-208 of the 398-amino acid-long GBS-PGK molecule. Substitution of the lysine residues within these regions with alanine resulted in significantly reduced binding to both actin and plasminogen. In addition, conversion of the glutamic acid residue at amino acid 133 to proline, the amino acid found at this position for the PGK protein of Streptococcus pneumoniae, also resulted in significantly reduced binding to actin and plasminogen. These results demonstrate that the lysine residues at amino acid positions 126, 127, 130, 204, and 208 along with the glutamic acid residue at amino acid position 133 are necessary for actin and plasminogen binding by GBS-PGK.

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    • "The complex globular structure of the octameric molecule hides C-terminal lysine residues in interdimer grooves, thereby maintaining structural integrity. Similarly, an internal binding site was recently discovered for the dimeric PGK of S. agalactiae and of S. pneumoniae, and also for the M-protein PAM of S. pyogenes (Boone and Tyrrell, 2012; Fulde et al., 2013b). The interaction of the M-like protein PAM with plasminogen is mediated by two N-terminally located repeat sequences designated a1 and a2. "
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