FIBER DIFFRACTION FROM FILAMENTOUS PLANT VIRUSES

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We are collecting fiber diffraction data from flexible filamentous plant viruses, invaluable as models for recognition, assembly, flexibility, viral-host interactions, and in methods development. Plant viruses have great potential in biotechnology, but development will require three-dimensional structures. Fiber diffraction is often the only method available for the determination of such filamentous structures. Diffraction samples are oriented sols and dried fibers. We find that order is better in dried fibers of highly flexible filaments, and in oriented sols of more rigid filaments. Dried fibers require much less material, an important consideration for studies of low-titer viruses. Wide and small angle diffraction data are collected at BioCAT. We have obtained fiber diffraction data from bean common mosaic virus and bean common mosaic necrosis virus, significantly improved both in orientation and in resolution by the use of high humidities in specimen preparation. We have obtained even better patterns from two strains of the related potyvirus soybean mosaic virus (SMV); these are the first diffraction data obtained from SMV, and the best diffraction data ever obtained from a member of the important Potyvirus family. They will be invaluable in determining high-resolution potyvirus structures. We have obtained excellent diffraction patterns from oriented sols of tobacco mosaic virus and potato virus X, made using a new method that requires less than 5% of the material needed for conventional methods, and involves much less handling (journal publication #3). The method will be extremely useful in fiber diffraction studies when samples are limited in quantity, labile, or hazardous.