HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Meehan, M. Articles by Owen, P. Search for Related Content PubMed PubMed Citation Articles by Meehan, M. Articles by Owen, P. Agricola Articles by Meehan, M. Articles by Owen, P.

Localization and characterization of the ligand-binding domain of the fibrinogen-binding protein (FgBP) of Streptococcus equi subsp. equi

National Pharmaceutical Biotechnology Centre, BioResearch, Ireland¹, and Department of Microbiology, Moyne Institute of Preventive Medicine², Trinity College, Dublin 2, Ireland

Author for correspondence: Peter Owen. Tel: +353 1 6081188. Fax: +353 1 6799294. e-mail: powen{at}tcd.ie

The group C streptococcus Streptococcus equi subsp. equi possesses a 498-residue major cell-wall-associated protein (FgBP) which binds horse fibrinogen (Fg), reacts with convalescent horse serum and protects against lethal S. equi challenge in a small animal model. In the present study, analysis of a panel of 17 purified N- and C-terminal FgBP truncates by ligand affinity blotting and SDS-PAGE revealed that the region required for maximum binding of Fg extended over the first half of the mature protein. The C-terminal two-thirds of this domain is predicted to be -helical coiled-coil and the N-terminal one-third to possess non-coiled-coil single strands. Residues at the extreme N-terminus and within the coiled-coil region are both required for ligand binding. A high incidence of -helical coiled-coil structure also seems to be responsible in part for the aberrant mobility of FgBP on SDS gels. The efficiency with which FgBP binds Fg from different animal species decreases in the order horse>mouse, pig>rat>sheep, dog, bovine, human. Binding to horse Fg is inversely related to temperature over the range 45–4 °C and is independent of Ca²⁺ ions. MS analysis provided corroborative evidence that FgBP is covalently linked to the cell wall peptidoglycan.

Keywords: Streptococcus equi subsp. equi, fibrinogen-binding protein, ligand-binding domain

Abbreviations: CD, circular dichroism; Fg, fibrinogen; FgBP, fibrinogen-binding protein; MALDI-TOF, matrix-assisted laser desorption/ionization time-of-flight

This article has been cited by other articles:

				M. J. Lewis, M. Meehan, P. Owen, and J. M. Woof A Common Theme in Interaction of Bacterial Immunoglobulin-binding Proteins with Immunoglobulins Illustrated in the Equine System J. Biol. Chem., June 20, 2008; 283(25): 17615 - 17623. [Abstract] [Full Text] [PDF]

				C. Kelly, M. Bugg, C. Robinson, Z. Mitchell, N. Davis-Poynter, J. R. Newton, K. A. Jolley, M. C. J. Maiden, and A. S. Waller Sequence Variation of the SeM Gene of Streptococcus equi Allows Discrimination of the Source of Strangles Outbreaks J. Clin. Microbiol., February 1, 2006; 44(2): 480 - 486. [Abstract] [Full Text] [PDF]

				H. Gutekunst, B. J. Eikmanns, and D. J. Reinscheid The Novel Fibrinogen-Binding Protein FbsB Promotes Streptococcus agalactiae Invasion into Epithelial Cells Infect. Immun., June 1, 2004; 72(6): 3495 - 3504. [Abstract] [Full Text] [PDF]

				C. Hennequin, C. Janoir, M.-C. Barc, A. Collignon, and T. Karjalainen Identification and characterization of a fibronectin-binding protein from Clostridium difficile Microbiology, October 1, 2003; 149(10): 2779 - 2787. [Abstract] [Full Text] [PDF]

				M. Meehan, Y. Lynagh, C. Woods, and P. Owen The fibrinogen-binding protein (FgBP) of Streptococcus equi subsp. equi additionally binds IgG and contributes to virulence in a mouse model Microbiology, December 1, 2001; 147(12): 3311 - 3322. [Abstract] [Full Text] [PDF]