1Division of Biology, Section of Virology and Oncology, Kansas State University, Manhattan, Kansas 66506
2U.S. Grain Marketing Research Laboratory, Science and Education Administration, Manhattan, Kansas 66502
Tóm tắt
Nucleocapsids were isolated from purified enveloped nucleocapsids of
Plodia interpunctella
granulosis virus by treatment with Nonidet P-40. When analyzed on sodium dodecyl sulfate-polyacrylamide gels, the nucleocapsids consisted of eight polypeptides. One of these, a major component with a molecular weight of 12,500 (VP12), was selectively extracted from the nucleocapsids with 0.25 M sulfuric acid. Its electrophoretic mobility on acetic acid-urea gels was intermediate to that of cellular histones and protamine. Amino acid analysis showed that 39% of the amino acid residues of VP12 were basic: 27% were arginine and 12% were histidine. The remaining residues consisted primarily of serine, valine, and isoleucine. Proteins of similar arginine content also were extracted from the granulosis virus of
Pieris rapae
and from the nuclear polyhedrosis viruses of
Spodoptera frugiperda
and
Autographa californica.
The basic polypeptide appeared to be virus specific because it was found in nucleocapsids and virus-infected cells but not in uninfected cells. VP12 was not present in polypeptide profiles of granulosis virus capsids, indicating that it was an internal or core protein of the nucleocapsids. Electron microscopic observations suggested that the basic protein was associated with the viral DNA in the form of a DNA-protein complex.
