Linked Life Data

8537367

Source:http://linkedlifedata.com/resource/pubmed/id/8537367

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
52
pubmed:dateCreated
1996-2-8
pubmed:databankReference
pubmed:abstractText
The comparison of four sequences of prokaryotic chitosanases, belonging to the family 46 of glycosyl hydrolases, revealed a conserved N-terminal module of 50 residues, including five invariant carboxylic residues. To verify if some of these residues are important for catalytic activity in the chitosanase from Streptomyces sp. N174, these 5 residues were replaced by site-directed mutagenesis. Substitutions of Glu-22 or Asp-40 with sterically conservative (E22Q, D40N) or functionally conservative (E22D, D40E) residues reduced drastically specific activity and kcat, while Km was only slightly changed. The other residues examined, Asp-6, Glu-36, and Asp-37, retained significant activity after mutation. Circular dichroism studies of the mutant chitosanases confirmed that the observed effects are not due to changes in secondary structure. These results suggested that Glu-22 and Asp-40 are directly involved in the catalytic center of the chitosanase and the other residues are not essential for catalytic activity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
29
pubmed:volume
270
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
31077-82
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Site-directed mutagenesis of evolutionary conserved carboxylic amino acids in the chitosanase from Streptomyces sp. N174 reveals two residues essential for catalysis.
pubmed:affiliation
Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Québec, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't