Linked Life Data

10600667

Source:http://linkedlifedata.com/resource/pubmed/id/10600667

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
Pt 1
pubmed:dateCreated
2000-2-17
pubmed:abstractText
Rotation of a motor protein, F(1)-ATPase, was demonstrated using a unique single-molecule observation system. This paper reviews what has been clarified by this system and then focuses on the role of residues at the hinge region of the beta subunit. We have visualised rotation of a single molecule of F(1)-ATPase by attaching a fluorescent actin filament to the top of the beta subunit in the immobilised F(1)-ATPase, thus settling a major controversy regarding the rotary catalysis. The rotation of the beta subunit was exclusively in one direction, as could be predicted by the crystal structure of bovine heart F(1)-ATPase. Rotation at low ATP concentrations revealed that one revolution consists of three 120 degrees steps, each fuelled by the binding of an ATP to the beta subunit. The mean work done by a 120 degrees step was approximately 80 pN nm, a value close to the free energy liberated by hydrolysis of one ATP molecule, implying nearly 100% efficiency of energy conversion. The torque is probably generated by the beta subunit, which undergoes large opening-closing domain motion upon binding of AT(D)P. We identified three hinge residues, betaHis179, betaGly180 and betaGly181, whose peptide bond dihedral angles are drastically changed during domain motion. Simultaneous substitution of these residues with alanine resulted in nearly complete loss (99%) of ATPase activity. Single or double substitution of the two Gly residues did not abolish the ATPase activity. However, reflecting the shift of the equilibrium between the open and closed forms of the beta subunit, single substitution caused changes in the propensity to generate the kinetically trapped Mg-ADP inhibited form: Gly180Ala enhanced the propensity and Gly181Ala abolished the propensity. In spite of these changes, the mean rotational torque was not changed significantly for any of the mutants.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0022-0949
pubmed:author
pubmed:issnType
Print
pubmed:volume
203
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1-8
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Rotation of F(1)-ATPase and the hinge residues of the beta subunit.
pubmed:affiliation
The Research Laboratory of Resources Utilization, Tokyo Institute of Technology, Yokohama 226-8503, Japan.
pubmed:publicationType
Journal Article, Review