Linked Life Data

9891001

Source:http://linkedlifedata.com/resource/pubmed/id/9891001

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1999-2-16
pubmed:databankReference
pubmed:abstractText
Directed evolution was used to change the substrate specificity of aspartate aminotransferase. A mutant enzyme with 17 amino acid substitutions was generated that shows a 2.1 x 10(6)-fold increase in the catalytic efficiency (kcat/Km) for a non-native substrate, valine. The absorption spectrum of the bound coenzyme, pyridoxal 5'-phosphate, is also changed significantly by the mutations. Interestingly, only one of the 17 residues appears to be able to contact the substrate, and none of them interact with the coenzyme. The three-dimensional structure of the mutant enzyme complexed with a valine analog, isovalerate (determined to 2.4-A resolution by x-ray crystallography), provides insights into how the mutations affect substrate binding. The active site is remodeled; the subunit interface is altered, and the enzyme domain that encloses the substrate is shifted by the mutations. The present results demonstrate clearly the importance of the cumulative effects of residues remote from the active site and represent a new line of approach to the redesign of enzyme activity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
22
pubmed:volume
274
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2344-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Redesigning the substrate specificity of an enzyme by cumulative effects of the mutations of non-active site residues.
pubmed:affiliation
Department of Biochemistry, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't