Purification of F 1-ATPase with impaired catalytic activity from partial revertants of Escherichia coliuncA mutant strains

Abstract

It is shown that F 1-ATPase preparations having impaired catalytic rates may be purified from partial revertants of uncA mutant strains of Escherichia coli. Recovery of catalytic activity in the partial revertant F 1 was accompanied by recovery of α ↔ β intersubunit conformational interaction, supporting the hypothesis that such interaction is required for normal catalysis in F 1. The specific ATPase activities of the partial revertant F 1 preparations were in the range 1–29% of normal, and some of the preparations showed unusual insensitivity to inhibitors. The properties of a new uncA mutant F 1 preparation ( uncA498) which has approximately half of normal catalytic rate are also briefly described.