STRUCTURE OF RIBGRASS MOSAIC-VIRUS AT 2.9 ANGSTROM RESOLUTION - EVOLUTION AND TAXONOMY OF TOBAMOVIRUSES

Ribgrass mosaic virus (RMV) is a member of the tobamovirus group of pl ant viruses. The structure has been determined at 2.9 Angstrom resolut ion by fiber diffraction methods, and refined by molecular dynamics me thods to an X-factor of 0.095. The carboxyl-carboxylate interactions t hat drive disassembly in tobamoviruses are present in RMV, but are ver y different from those in other tobamoviruses. RMV has some of the str uctural features of a subgroup I tobamovirus, a smaller number from su bgroup II, and a number that appear to be unique to the RMV cluster of viruses. The structural studies confirm the evolutionary and taxonomi c separation of the RMV cluster from both subgroup I and subgroup II t obamoviruses. (C) 1997 Academic Press Limited.