This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1nbm
From Proteopedia
|
THE STRUCTURE OF BOVINE F1-ATPASE COVALENTLY INHIBITED WITH 4-CHLORO-7-NITROBENZOFURAZAN
Overview
BACKGROUND: F1-ATPase is the globular domain of F1F0-ATP synthase that catalyses the hydrolysis of ATP to ADP and phosphate. The crystal structure of bovine F1-ATPase has been determined previously to 2.8 A resolution. The enzyme comprises five different subunits in the stoichiometry alpha 3 beta 3 gamma delta epsilon; the three catalytic beta subunits alternate with the three alpha subunits around the centrally located single gamma subunit. To understand more about the catalytic mechanisms, F1-ATPase was inhibited by reaction with 4-chloro-7-nitrobenzofurazan (NBD-Cl) and the structure of the inhibited complex (F1-NBD) determined by X-ray crystallography. RESULTS: In the structure the three beta subunits adopt a different conformation with different nucleotide occupancy. NBD-Cl reacts with the phenolic oxygen of Tyr311 of the beta E subunit, which contains no bound nucleotide. The two other catalytic subunits beta TP and beta DP contain bound adenylyl-imidodiphosphate (AMP-PNP) and ADP, respectively. The binding site of the NBD moiety does not overlap with the regions of beta E that form the nucleotide-binding pocket in subunits beta TP and beta DP nor does it occlude the nucleotide-binding site. Catalysis appears to be inhibited because neither beta TP nor beta DP can accommodate a Tyr311 residue bearing an NBD group. CONCLUSIONS: The results presented here are consistent with a rotary catalytic mechanism of ATP synthesis and hydrolysis, which requires the sequential and concerted participation of all three catalytic sites. NBD-Cl inhibits the enzyme by preventing the modified subunit from adopting a conformation that is essential for catalysis to proceed.
About this Structure
1NBM is a Protein complex structure of sequences from Bos taurus with , , and as ligands. Active as Transferred entry: 3.6.3.14, with EC number 3.6.1.34 Known structural/functional Sites: , , , , , , , , and . Full crystallographic information is available from OCA.
Reference
Bovine F1-ATPase covalently inhibited with 4-chloro-7-nitrobenzofurazan: the structure provides further support for a rotary catalytic mechanism., Orriss GL, Leslie AG, Braig K, Walker JE, Structure. 1998 Jul 15;6(7):831-7. PMID:9687365
Page seeded by OCA on Thu Feb 21 14:04:22 2008
