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Double-lock ratchet...
Double-lock ratchet mechanism revealing the role of alpha SER-344 in FoF1 ATP synthase
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- Beke-Somfai, Tamas, 1977 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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- Lincoln, Per, 1958 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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- Nordén, Bengt, 1945 (författare)
- Chalmers tekniska högskola,Chalmers University of Technology
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(creator_code:org_t)
- 2011-03-07
- 2011
- Engelska.
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 108:12, s. 4828-4833
- Relaterad länk:
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http://dx.doi.org/10...
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http://www.pnas.org/...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- In a majority of living organisms, FoF1 ATP synthase performs the fundamental process of ATP synthesis. Despite the simple net reaction formula, ADP + Pi. ATP + H2O, the detailed step-by-step mechanism of the reaction yet remains to be resolved owing to the complexity of this multisubunit enzyme. Based on quantum mechanical computations using recent high resolution X-ray structures, we propose that during ATP synthesis the enzyme first prepares the inorganic phosphate for the gamma P-O-ADP bond-forming step via a double-proton transfer. At this step, the highly conserved alpha S344 side chain plays a catalytic role. The reaction thereafter progresses through another transition state (TS) having a planar PO3- ion configuration to finally form ATP. These two TSs are concluded crucial for ATP synthesis. Using stepwise scans and several models of the nucleotide-bound active site, some of the most important conformational changes were traced toward direction of synthesis. Interestingly, as the active site geometry progresses toward the ATP-favoring tight binding site, at both of these TSs, a dramatic increase in barrier heights is observed for the reverse direction, i.e., hydrolysis of ATP. This change could indicate a "ratchet" mechanism for the enzyme to ensure efficacy of ATP synthesis by shifting residue conformation and thus locking access to the crucial TSs.
Ämnesord
- NATURVETENSKAP -- Kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences (hsv//eng)
Nyckelord
- qm/mm
- resolution
- reaction mechanism
- bovine heart-mitochondria
- hydrolysis
- quantum mechanics
- rotational catalysis
- catalytic sites
- f-1-atpase
- conformational change
- molecular motor
- methods
- enzymatic catalysis
- escherichia-coli
Publikations- och innehållstyp
- art (ämneskategori)
- ref (ämneskategori)
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