Staphylococcal protein A binding to VH3 encoded immunoglobulins.
Staphylococcal protein A (SPA) is a B-cell superantigen which binds specifically to the variable region of human VH3 encoded antibodies. We undertook to identify the VH3 regions involved in the interaction with SPA by producing mutant antibodies in the baculovirus expression system. We had previously shown that a single amino acid change at position 57 in the CDR2 of a human SPA nonbinding VH3 encoded rheumatoid factor converted it to an SPA binder, implicating CDR2 in SPA binding. When regions of the mutated binder were exchanged with those from a mouse nonbinding antibody, the pattern of SPA binding indicated that residues in FR1, CDR2 and FR3 are involved in the interaction between VH3 encoded antibodies and SPA. In addition, all three regions are simultaneously required for SPA binding to occur. When any one of the three regions was altered, SPA binding was severely disrupted.
Potter
K N
KN
Department of Microbiology, University of Texas, Southwestern Medical Center, Dallas 75235, USA.
Li
Y
Y
Pascual
V
V
Capra
J D
JD
D000595:Amino Acid Sequence; D000818:Animals; D001666:Binding Sites, Antibody / Q000235:genetics; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007135:Immunoglobulin Variable Region / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D013205:Staphylococcal Protein A / Q000378:metabolism*
D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; D011994:Recombinant Proteins; D013205:Staphylococcal Protein A