Linked Life Data

9784252

Source:http://linkedlifedata.com/resource/pubmed/id/9784252

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1998-11-13
pubmed:abstractText
Horse liver alcohol dehydrogenase contains two tryptophan residues per subunit, Trp-15 on the surface of the catalytic domain and Trp-314 buried in the interface between the subunits of the dimer. We studied the contributions of the tryptophans to fluorescence and catalytic dynamics by substituting Trp-314 with a leucine residue and making two compensatory mutations that were required to obtain a stable protein, leading to the triple mutant M303F-L308I-W314L enzyme. The substitutions increased by two- to sixfold the turnover numbers for ethanol oxidation, acetaldehyde reduction, and the dissociation constants of the coenzymes. The rate of the exponential burst phase for the transient oxidation of ethanol increased slightly, but the rate of dissociation of the enzyme-NADH complex still limited turnover of ethanol, as for wild-type enzyme. The three substitutions at the dimer interface apparently activate the enzyme by allowing more rapid conformational changes that accompany coenzyme binding, probably due to movement of the loop containing residues 293 to 298. The emission spectrum of M303F-L308I-W314L enzyme, which contains Trp-15, was redshifted compared to wild-type enzyme. Time-resolved fluorescence measurements with the triple mutant show that the decay of Trp-15 is dominated by a approximately 7-ns component. In the mutant enzyme with Trp-15 substituted with phenylalanine, the decay of Trp-314 is dominated by a approximately 4-ns component. Solute quenching data for wild-type enzyme and the mutants show that only Trp-15 is exposed to iodide and acrylamide, whereas Trp-314 is inaccessible. The luminescence properties of the tryptophan residues in the mutated enzymes are consistent with conclusions from studies of the wild-type enzyme [M. R. Eftink, 1992, Adv. Biophys. Chem. 2, 81-114].
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0003-9861
pubmed:author
pubmed:copyrightInfo
Copyright 1998 Academic Press.
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
358
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
369-76
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Activation of horse liver alcohol dehydrogenase upon substitution of tryptophan 314 at the dimer interface.
pubmed:affiliation
Department of Biochemistry, The University of Iowa, Iowa City, Iowa, 52242, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.