Linked Life Data

2261461

Source:http://linkedlifedata.com/resource/pubmed/id/2261461

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
35
pubmed:dateCreated
1991-2-7
pubmed:abstractText
To quantitate the contributions of the large hydrophobic residues in staphylococcal nuclease to the stability of its native state, single alanine and glycine substitutions were constructed by site-directed mutagenesis for each of the 11 leucine, 9 valine, 7 tyrosine, 5 isoleucine, 4 methionine, and 3 phenylalanine residues. In addition, each isoleucine was also mutated to valine. The resulting collection of 83 mutant nucleases was submitted to guanidine hydrochloride denaturation using intrinsic tryptophan fluorescence to monitor the equilibrium constant between the native and denatured states. From analysis of these data, each mutant protein's stability to reversible denaturation (delta GH2O) and sensitivity to guanidine hydrochloride (mGuHCl or d(delta G)/d[GuHCl]) were obtained. Four unexpected trends were observed. (1) A striking bipartite distribution was found for sites of mutations that altered mGuHCl: mutations that increased this parameter only involved residues that contribute side chains to the major hydrophobic core centered around a five-strand beta-barrel, whereas mutations that caused mGuHCl to decrease clustered around a second, smaller and less well-defined hydrophobic core. (2) The average stability loss for mutants in each of the six residue classes was 2-3 times greater than that estimated on the basis of the free energy of transfer of the hydrophobic side chain from water to n-octanol. (3) The magnitude of the stability loss on substituting Ala or Gly for a particular type of amino acid varied extensively among the different sites of its occurrence in nuclease, indicating that the environment surrounding a specific residue determines how large a stability contribution its side chain will make.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
8033-41
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Contributions of the large hydrophobic amino acids to the stability of staphylococcal nuclease.
pubmed:affiliation
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.