THE STRUCTURE OF AN IMMUNODOMINANT LOOP ON FOOT-AND-MOUTH-DISEASE VIRUS, SEROTYPE-01, DETERMINED UNDER REDUCING CONDITIONS

Residues 136-159 of VPI of foot and mouth disease virus (FMDV) compris e the G-H loop of the protein and form a prominent feature on the surf ace of virus particles. This sequence contains an immunodominant neutr alizing epitope, which can be mimicked with synthetic peptides, and in cludes an Arg, Gly, Asp motif which has been implicated in the binding of the virus to cellular receptors. Crystallographic analysis of nati ve virus particles failed to resolve the structure of this region due to its disordered state. However, reduction of a disulphide bond betwe en cysteine residues 134 of VP1 and 130 of VP2 caused the G-H loop to collapse onto the surface of the virus particle and allowed its confor mation to be determined.