Molecular Arrangement in Tobacco Necrosis Virus Crystals

Abstract

AN electron micrograph has already been published¹ showing elementary particles of the tobacco necrosis virus in the kind of symmetrical arrangement to be expected if they form part of a single crystal. Photographs have now been obtained which record the regular molecular distribution over several faces of polyhedra of this virus, and thereby demonstrate their truly crystalline structure. The preparations that show this have been atomic replicas made as in the earlier work, except that palladium has often been used as shadowing material instead of gold. This metal can also be stripped from glass and, as would be expected from its higher melting and boiling points, gives films less readily damaged under electron impact.