During the last year we have solved two new virus structures and we are on the verge of solving a third with data collected at CHESS. Three virus structures related to the RNA insect pathogen Flock House Virus (FHV) were also determined with CHESS data. We have generated a 5? electron density map of the first dsDNA bacteriophage capsid, HK97 (P21 a=580, b=625, c=790?, beta=90.0o). This structure, currently being extended to 3.5? resolution, is the first example of a particle that undergoes a large scale maturation polymorphism. Our structure is of the mature head which is ~650? in diameter. This map was the result of collecting two different data sets (100? resolution to 7? and 20? resolution to 4.3?) at CHESS with exceptional help and support from MacCHESS personnel. We also solved the structure of cricket paralysis virus (CrPV) which is the first example of a picorna-like insect virus. This structure is being refined at 2.4? resolution. Unlike normal mamallian picornaviruses, the structural proteins are at the 3 end of the RNA and the VP4 chain is cleaved from the N terminus of VP3, not from the N terminus of VP2. Finally we are on the verge of solving the structure of rice yellow mottle virus (RYMV), the cause of one of the most devasting losses in food crops in Africa. Finally, we solved four mutants of FHV that are virus-like particles produced in a baculovirus expression system. The first was the wild type recombinant particle, the second a non cleaving mutant, the third an assembly mutant that produced a statistical distribution of particles including a T=3 particle that crsyatllized and diffracted x-rays to 2.4?. All three structures have lead to new understanding of the viral biology.
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