Linked Life Data

9228021

Source:http://linkedlifedata.com/resource/pubmed/id/9228021

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
30
pubmed:dateCreated
1997-9-9
pubmed:databankReference
pubmed:abstractText
The structural determinants of substrate recognition in the human class IV, or sigmasigma, alcohol dehydrogenase (ADH) isoenzyme were examined through x-ray crystallography and site-directed mutagenesis. The crystal structure of sigmasigma ADH complexed with NAD+ and acetate was solved to 3-A resolution. The human beta1beta1 and sigmasigma ADH isoenzymes share 69% sequence identity and exhibit dramatically different kinetic properties. Differences in the amino acids at positions 57, 116, 141, 309, and 317 create a different topology within the sigmasigma substrate-binding pocket, relative to the beta1beta1 isoenzyme. The nicotinamide ring of the NAD(H) molecule, in the sigmasigma structure, appears to be twisted relative to its position in the beta1beta1 isoenzyme. In conjunction with movements of Thr-48 and Phe-93, this twist widens the substrate pocket in the vicinity of the catalytic zinc and may contribute to this isoenzyme's high Km for small substrates. The presence of Met-57, Met-141, and Phe-309 narrow the middle region of the sigmasigma substrate pocket and may explain the substantially decreased Km values with increased chain length of substrates in sigmasigma ADH. The kinetic properties of a mutant sigmasigma enzyme (sigma309L317A) suggest that widening the middle region of the substrate pocket increases Km by weakening the interactions between the enzyme and smaller substrates while not affecting the binding of longer alcohols, such as hexanol and retinol.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
272
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
18558-63
pubmed:dateRevised
2009-9-9
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
X-ray structure of human class IV sigmasigma alcohol dehydrogenase. Structural basis for substrate specificity.
pubmed:affiliation
Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.