Linked Life Data

2326253

Source:http://linkedlifedata.com/resource/pubmed/id/2326253

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1990-5-14
pubmed:abstractText
An attempt has been made to identify residues in T4 phage lysozyme that may have strained conformations and, by appropriate site-directed replacements, to reduce this strain and thus increase the thermostability of the protein. Valine 131, within alpha-helix 126-134, was identified as a potential candidate. Its side-chain rotational angle, chi 1, differs by approximately 18 degrees from the low-energy trans configuration. In addition, it is largely solvent exposed, yet is held in a rigid conformation. The mutant protein with Val 131 replaced by alanine was constructed and found to have a melting temperature 0.9 degrees C higher than that of wild-type lysozyme at pH 2.8. As a control, the mutant Val 131----Thr was also constructed and its melting temperature was found to be marginally lower than wild type. High-resolution crystal structure determinations of the mutant lysozymes show that their structures are virtually identical with that of wild-type lysozyme, except for the Val----Ala or Val----Thr replacement. Analysis of the different structures suggests that the design of the Val----Ala substitution was, in principle, successful, although the apparent gain in stability caused by reduction in strain is modest and is somewhat offset by the loss of hydrophobic interactions and by entropic effects. The results also help to provide a structural rationalization for the experimental and empirical observations that alanine has a higher helix propensity than valine or threonine.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0887-3585
pubmed:author
pubmed:issnType
Print
pubmed:volume
7
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
198-204
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
A mutant T4 lysozyme (Val 131----Ala) designed to increase thermostability by the reduction of strain within an alpha-helix.
pubmed:affiliation
Institute of Molecular Biology, University of Oregon, Eugene 97403.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't