Linked Life Data

12902331

Source:http://linkedlifedata.com/resource/pubmed/id/12902331

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
42
pubmed:dateCreated
2003-10-13
pubmed:abstractText
Gastric tissues from amphibian Rana perezi express the only vertebrate alcohol dehydrogenase (ADH8) that is specific for NADP(H) instead of NAD(H). In the crystallographic ADH8-NADP+ complex, a binding pocket for the extra phosphate group of coenzyme is formed by ADH8-specific residues Gly223-Thr224-His225, and the highly conserved Leu200 and Lys228. To investigate the minimal structural determinants for coenzyme specificity, several ADH8 mutants involving residues 223 to 225 were engineered and kinetically characterized. Computer-assisted modeling of the docked coenzymes was also performed with the mutant enzymes and compared with the wild-type crystallographic binary complex. The G223D mutant, having a negative charge in the phosphate-binding site, still preferred NADP(H) over NAD(H), as did the T224I and H225N mutants. Catalytic efficiency with NADP(H) dropped dramatically in the double mutants, G223D/T224I and T224I/H225N, and in the triple mutant, G223D/T224I/H225N (kcat/KmNADPH = 760 mm-1 min-1), as compared with the wild-type enzyme (kcat/KmNADPH = 133330 mm-1 min-1). This was associated with a lower binding affinity for NADP+ and a change in the rate-limiting step. Conversely, in the triple mutant, catalytic efficiency with NAD(H) increased, reaching values (kcat/KmNADH = 155000 mm-1 min-1) similar to those of the wild-type enzyme with NADP(H). The complete reversal of ADH8 coenzyme specificity was therefore attained by the substitution of only three consecutive residues in the phosphate-binding site, an unprecedented achievement within the ADH family.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
278
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
40573-80
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Complete reversal of coenzyme specificity by concerted mutation of three consecutive residues in alcohol dehydrogenase.
pubmed:affiliation
Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Barcelona), Spain.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't