ATP Phosphohydrolase (ATPase) Activity of a Polyoma Virus T Antigen

Abstract

Among the various polyoma virus T antigens which have so far been identified, only the large‐T and a 63000‐Mr polypeptide were found to bind to double‐stranded calf thymus DNA. The proteins were not retained on single‐stranded DNA‐cellulose columns, and a purification procedure was designed on the basis of this observation. Purified fractions (approx. 1000‐fold) exhibited an enzymatic activity which converts ATP into ADP and Pi. This activity was quantitatively inhibited after preincubation in the presence of anti‐(polyoma T antigen) immunoglobulins and was shown to be dependent on a virus‐coded gene product (a gene) on the basis of the following observations: (a) ATPase activity from cells infected with tsa mutants of polyoma was reduced after a shift to the restrictive temperature; (b) the enzyme purified from tsa‐infected cells maintained at the permissive temperature was more thermolabile in vitro than that prepared in parallel from cells infected with wild‐type virus. Copyright © 1980, Wiley Blackwell. All rights reserved