Linked Life Data

10906329

Source:http://linkedlifedata.com/resource/pubmed/id/10906329

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
41
pubmed:dateCreated
2000-11-13
pubmed:abstractText
Enzymes isolated from organisms native to cold environments generally exhibit higher catalytic efficiency at low temperatures and greater thermosensitivity than their mesophilic counterparts. In an effort to understand the evolutionary process and the molecular basis of cold adaptation, we have used directed evolution to convert a mesophilic subtilisin-like protease from Bacillus sphaericus, SSII, into its psychrophilic counterpart. A single round of random mutagenesis followed by recombination of improved variants yielded a mutant, P3C9, with a catalytic rate constant (k(cat)) at 10 degrees C 6.6 times and a catalytic efficiency (k(cat)/K(M)) 9.6 times that of wild type. Its half-life at 70 degrees C is 3.3 times less than wild type. Although there is a trend toward decreasing stability during the progression from mesophile to psychrophile, there is not a strict correlation between decreasing stability and increasing low temperature activity. A first generation mutant with a >2-fold increase in k(cat) is actually more stable than wild type. This suggests that the ultimate decrease in stability may be due to random drift rather than a physical incompatibility between low temperature activity and high temperature stability. SSII shares 77. 4% identity with the naturally psychrophilic protease subtilisin S41. Although SSII and S41 differ at 85 positions, four amino acid substitutions were sufficient to generate an SSII whose low temperature activity is greater than that of S41. That none of the four are found in S41 indicates that there are multiple routes to cold adaptation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
13
pubmed:volume
275
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
31635-40
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Cold adaptation of a mesophilic subtilisin-like protease by laboratory evolution.
pubmed:affiliation
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't