Alteration of the nucleoside triphosphate (NTP) catalytic domain within Escherichia coli recA protein attenuates NTP hydrolysis but not joint molecule formation.

摘要: The hydrolysis of the nucleoside triphosphates, such as ATP or GTP, plays a central role in variety biochemical processes; but, most cases, specific mechanism energy transduction is unclear. DNA strand exchange promoted by Escherichia coli recA protein normally associated with hydrolysis. However, we advanced idea that observed not obligatorily linked to strands (Menetski, J. P., Bear, D. G., and Kowalczykowski, S. C. (1990) Proc. Natl. Acad. Sci. U. A. 87, 21-25); instead, binding resulting an allosteric transition active form sufficient. In this paper, extend conclusion introducing mutation within highly conserved region that, on basis sequence similarity, proposed interact pyrophosphate moiety bound NTP molecule. conservative substitution arginine for invariant lysine at position 72 reduces approximately 600-850-fold. This does significantly alter capacity mutant (K72R) either bind nucleotide cofactors single-stranded respond allosterically cofactor binding. Despite dramatic attenuation hydrolysis, retains ability promote homologous pairing extensive (up 1.5 kilobase pairs). These results both identify component catalytic domain demonstrate protein-promoted mechanistically require induced binding, but educed from