Functional Halt Positions of Rotary FOF1-ATPase Correlated with Crystal Structures

Autor(en): Sielaff, Hendrik
Rennekamp, Henning
Engelbrecht, Siegfried
Junge, Wolfgang 
Stichwörter: ANGSTROM RESOLUTION; ATP SYNTHASE; Biophysics; BOVINE F-1-ATPASE; CATALYTIC SITES; ESCHERICHIA-COLI; F-ATPASE; MECHANISM; ROTATION; SITE-DIRECTED MUTAGENESIS; VISCOELASTIC DYNAMICS
Erscheinungsdatum: 2008
Herausgeber: BIOPHYSICAL SOC
Journal: BIOPHYSICAL JOURNAL
Volumen: 95
Ausgabe: 10
Startseite: 4979
Seitenende: 4987
Zusammenfassung: 
The FOF1-ATPase is a rotary molecular motor. Driven by ATP-hydrolysis, its central shaft rotates in 80 degrees and 40 degrees steps, interrupted by catalytic and ATP-waiting dwells. We recorded rotations and halts by means of microvideography in laboratory coordinates. A correlation with molecular coordinates was established by using an engineered pair of cysteines that, under oxidizing conditions, formed zero-length cross-links between the rotor and the stator in an orientation as found in crystals. The fixed orientation coincided with that of the catalytic dwell, whereas the ATP waiting dwell was displaced from it by 40 degrees. In crystals, the convex side of the cranked central shaft faces an empty nucleotide binding site, as if holding it open for arriving ATP. Functional studies suggest that three sites are occupied during a catalytic dwell. Our data imply that the convex side faces a nucleotide-occupied rather than an empty site. The enzyme conformation in crystals seems to differ from the conformation during either dwell of the active enzyme. A revision of current schemes of the mechanism is proposed.
ISSN: 00063495
DOI: 10.1529/biophysj.108.139782

Show full item record

Page view(s)

2
Last Week
0
Last month
1
checked on Feb 22, 2024

Google ScholarTM

Check

Altmetric