Electron microscopy of partially degraded tobacco mosaic virus

Abstract

Electron microscopy of purified preparations of tobacco mosaic virus (TMV) that had been treated with phenol revealed particles from which the protein had been stripped from one end only, particles from which the protein had been removed from both ends, particles from which protein had been removed from one or more places in the middle of the rod, and still other particles from which no protein at all had been removed. It appears, therefore, that degradation of TMV by phenol occurs in a random fashion along the virus rod. Numerous long ribonucleic acid threads were found in all preparations. Some of the partially degraded virus particles were approximately 3000 A long and 200 A wide. The exposed nucleic acid of such particles was approximately 66 A wide. Partially degraded preparations were about 1 200 as infectious as the intact virus, and when such preparations were incubated with ribonuclease the infectivity was almost completely lost.