1: J Biol Chem  2002 Mar 5; [epub ahead of print] 

F1-ATPase changes its conformations upon phosphate release.

Masaike T, Muneyuki E, Noji H, Kinosita K Jr, Yoshida M.

Chemical Resources Laboratory, Tokyo Institute of Technology, Yokohama,
Kanagawa-ken 226-8503.

Motor proteins, myosin and kinesin, have gamma-phosphate sensors in the switch
II loop that play key roles in conformational changes that support motility.
Here we report that a rotary motor, F(1)-ATPase, also changes its conformations
upon phosphate release. The tryptophan mutation was introduced into Arg333 in
the betasubunit of F(1)-ATPase from thermophilic Bacillus PS3 as a probe of
conformational changes. This residue interacts with the switch II loop (residues
308-315) of the beta subunit in a nucleotide bound conformation. Addition of ATP
to the mutant F(1) subcomplex alpha(3)beta(R333W)(3)gamma caused transient
increase and subsequent decay of the Trp fluorescence. The increase was caused
by conformational changes on ATP binding. The rate of decay agreed well with
that of phosphate release monitored by phosphate binding protein assays. This is
the first evidence that the beta subunit changes its conformation upon phosphate
release, which may share a common mechanism of exerting motility with other
motor proteins.

PMID: 11880367 [PubMed - as supplied by publisher]