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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
28
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pubmed:dateCreated |
1995-8-25
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pubmed:abstractText |
Mutations in the beta subunit of Escherichia coli proton-translocating nicotinamide nucleotide transhydrogenase of the conserved residue beta Asp-213 to Asn (beta D213N) and Ile (beta D213I) resulted in the loss, respectively, of about 70% and 90% NADPH-->3-acetylpyridine adenine dinucleotide (AcPyAD) transhydrogenation and coupled proton translocation activities. However, the cyclic NADP(H)-dependent NADH-->AcPyAD transhydrogenase activities of the mutants were only approximately 35% inhibited. The latter transhydrogenation, which is not coupled to proton translocation, occurs apparently via NADP under conditions that enzyme-NADP(H) complex is stabilized. Mutations beta D213N and beta D213I also resulted in decreases in apparent KmNADPH for the NADPH-->AcPyAD and S0.5NADPH (NADPH concentration needed for half-maximal activity) for the cyclic NADH-->AcPyAD transhydrogenation reactions, and in KdNADPH, as determined by equilibrium binding studies on the purified wild-type and the beta D213I mutant enzymes. These results point to a structural role of beta Asp-213 in energy transduction and are discussed in relation to our previous suggestion that proton translocation coupled to NADPH-->NAD (or AcPyAD) transhydrogenation is driven mainly by the difference in the binding energies of NADPH and NADP.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Jul
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
14
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pubmed:volume |
270
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
16653-9
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pubmed:dateRevised |
2011-11-17
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pubmed:meshHeading |
pubmed-meshheading:7622474-Amino Acid Sequence,
pubmed-meshheading:7622474-Escherichia coli,
pubmed-meshheading:7622474-Molecular Sequence Data,
pubmed-meshheading:7622474-Mutation,
pubmed-meshheading:7622474-NAD,
pubmed-meshheading:7622474-NADP,
pubmed-meshheading:7622474-NADP Transhydrogenases,
pubmed-meshheading:7622474-Structure-Activity Relationship
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pubmed:year |
1995
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pubmed:articleTitle |
Proton-translocating nicotinamide nucleotide transhydrogenase of Escherichia coli. Involvement of aspartate 213 in the membrane-intercalating domain of the beta subunit in energy transduction.
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pubmed:affiliation |
Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California 92037, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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