Isolation of an arginine-rich protein from particles of adenovirus type 2

Abstract

Polyacrylamide gel electrophoresis showed that particles of adenovirus type 2, disrupted with hot sodium dodecyl sulphate (SDS) and dithiothreitol, contained nine protein components (bands 1–9) with molecular weights ranging from 190,000 to 11,000. Four of these components (bands 6, 7, 8 and 9) were isolated by preparative acrylamide gel electrophoresis, following a preliminary fractionation of the proteins by stepwise ethanol precipitation in the presence of guanidine hydrochloride. One component (band 2) was isolated by the latter procedure alone. The protein in band 8, one of the core proteins of the virus, was found to contain 23% of arginine. It also had an unusually high content of alanine (20%). This very arginine-rich protein had a molecular weight of approximately 18,000 and possessed a free N-terminal alanine residue. The protein in band 2 (which was isolated solely by ethanol fractionation in the presence of guanidine hydrochloride) had a molecular weight of approximately 120,000. It probably contained only the hexon protein of the virus, as it had the same amino acid composition and showed the same pattern of tryptic peptides as the hexon of adenovirus type 2 crystallized from the soluble antigen fraction of infected cell extracts.