1: Proc Natl Acad Sci U S A  2001 Nov 20;98(24):13649-54 

Pause and rotation of F(1)-ATPase during catalysis.

Hirono-Hara Y, Noji H, Nishiura M, Muneyuki E, Hara KY, Yasuda R, Kinosita K Jr,
Yoshida M.

Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta,
Yokohama 226-8503, Japan.

F(1)-ATPase is a rotary motor enzyme in which a single ATP molecule drives a 120
degrees rotation of the central gamma subunit relative to the surrounding
alpha(3)beta(3) ring. Here, we show that the rotation of F(1)-ATPase
spontaneously lapses into long (approximately 30 s) pauses during steady-state
catalysis. The effects of ADP-Mg and mutation on the pauses, as well as kinetic
comparison with bulk-phase catalysis, strongly indicate that the paused enzyme
corresponds to the inactive state of F(1)-ATPase previously known as the ADP-Mg
inhibited form in which F(1)-ATPase fails to release ADP-Mg from catalytic
sites. The pausing position of the gamma subunit deviates from the ATP-waiting
position and is most likely the recently found intermediate 90 degrees position.

PMID: 11707579 [PubMed - indexed for MEDLINE]