Blackmore, T.Fischetti, V.Sadlon, T.Ward, H.Gordon, D.2014-01-242014-01-241998Infection and Immunity, 1998; 66(4):1427-14310019-95671098-5522http://hdl.handle.net/2440/81791Streptococcus pyogenes evades complement by binding the complement-regulatory protein factor H (fH) via the central conserved C-repeat region of M protein. However, the corresponding binding region within fH has not previously been precisely localized. fH is composed of 20 conserved modules called short consensus repeats (SCRs), each of which contains approximately 60 amino acids. A series of fH truncated and deletion mutants were prepared, and their interaction with M6 protein was examined. The M protein binding site was initially localized to SCRs 6 to 15 as demonstrated by ligand dot blotting, chemical cross-linking, and enzyme-linked immunosorbent assay. SCR 7 was then shown to contain the M protein binding site, as a construct consisting of the first seven SCRs bound M protein but a construct containing the first six SCRs did not bind. In addition, deletion of SCR 7 from full-length fH abolished binding to M protein. SCR 7 is known to contain a heparin binding domain, and binding of fH to M6 protein was almost totally inhibited in the presence of 400 U of heparin per ml. These results localize the M6 protein binding site of fH to SCR 7 and indicate that it is in close proximity to the heparin binding site.enCopyright © 1998 American Society for MicrobiologyCHO CellsAnimalsHumansStreptococcus pyogenesHeparinBacterial ProteinsBacterial Outer Membrane ProteinsComplement Factor HCarrier ProteinsAntigens, BacterialBinding SitesCricetinaeJournal article00300002192014012408120510.1128/iai.66.4.1427-1431.199892 Health9201 Clinical Health (Organs, Diseases and Abnormal Conditions)920108 Immune System and Allergy11 Medical and Health Sciences1107 Immunology110706 Immunogenetics (incl. Genetic Immunology)0000727061000222-s2.0-003203866564225Ward, H. [0000-0002-3831-1205]