Linked Life Data

18157952

Source:http://linkedlifedata.com/resource/pubmed/id/18157952

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2008-4-28
pubmed:abstractText
Leucine aminopeptidase (LAP) is an exopeptidase that catalyzes the hydrolysis of amino acid residues from the amino terminus of proteins and peptides. Sequence alignment shows that the conserved Ala348 and Gly350 residues of Bacillus kaustophilus LAP (BkLAP) are located right next to a coordinated ligand. We further investigated the roles of these two residues by performing computer modeling and site-directed mutagenesis. Based on the modeling, the carbonyl group of Ala348 interacts with Asn345 and Asn435, and that of Gly350 with Ile353 and Leu354, where these interactions might maintain the zinc-coordinated residues at their correct positions. Replacement of Ala348 with Arg resulted in a dramatic reduction in LAP activity. A complete loss of the activity was also observed in A348E, A348V, and the Gly350 variants. Measurement of intrinsic tryptophan fluorescence revealed alteration of the microenvironment of aromatic amino acid residues, while circular dichroism spectra were nearly identical for wild-type and all mutant enzymes. Protein modeling and site-directed mutagenesis suggest that residues Ala348 and Gly350 are essential for BkLAP in maintaining a stable active-site environment for the catalytic reaction.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0300-9084
pubmed:author
pubmed:issnType
Print
pubmed:volume
90
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
811-9
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Site-directed mutagenesis of the conserved Ala348 and Gly350 residues at the putative active site of Bacillus kaustophilus leucine aminopeptidase.
pubmed:affiliation
Department of Chemistry and Biochemistry, National Chung Cheng University, Chiayi, Taiwan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't