1nbm: Difference between revisions
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==Overview== | ==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. ... | 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== | ==About this Structure== | ||
1NBM is a | 1NBM is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with MG, PO4, ATP and ADP as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Transferred_entry:_3.6.3.14 Transferred entry: 3.6.3.14], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.6.1.34 3.6.1.34] Structure known Active Sites: CA1, CA2, CA3, PL1, PL2, PL3, PL4, PL5, PL6 and PL7. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1NBM OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: inhibition]] | [[Category: inhibition]] | ||
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Revision as of 13:29, 5 November 2007
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THE STRUCTURE OF BOVINE F1-ATPASE COVALENTLY INHIBITED WITH 4-CHLORO-7-NITROBENZOFURAZAN
OverviewOverview
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 StructureAbout this Structure
1NBM is a Protein complex structure of sequences from Bos taurus with MG, PO4, ATP and ADP as ligands. Active as Transferred entry: 3.6.3.14, with EC number 3.6.1.34 Structure known Active Sites: CA1, CA2, CA3, PL1, PL2, PL3, PL4, PL5, PL6 and PL7. Full crystallographic information is available from OCA.
ReferenceReference
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
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