|
rdf:type |
|
|
lifeskim:mentions |
|
|
pubmed:issue |
2
|
|
pubmed:dateCreated |
1995-8-17
|
|
pubmed:abstractText |
The structures of two mutant forms (G240A and L246E/V249M) of 3-isopropylmalate dehydrogenase from Thermus thermophilus HB8 were studied by X-ray crystallography. In the case of G240A, the replacement of glycine by alanine at residue 240 was expected to decrease the thermostability as a result of abnormal contacts between the methyl group of alanine and the peptide chain. However, the normal van der Waals' contacts were achieved owing to a shift in a bundle of beta-strands that yielded a vacant space for the alanine residue. The extended hydrogen bonds within the beta-sheet are the major reason for the decreased thermostability of G240A. The mutations in L246E/V249M are located in an alpha-helix region which is involved in subunit-subunit contact via hydrophobic interaction. Loosening of the subunit-subunit contact owing to ionic repulsion was the major cause of the lower heat stability of L246E/V249M.
|
|
pubmed:language |
eng
|
|
pubmed:journal |
|
|
pubmed:citationSubset |
IM
|
|
pubmed:chemical |
|
|
pubmed:status |
MEDLINE
|
|
pubmed:month |
Feb
|
|
pubmed:issn |
0021-924X
|
|
pubmed:author |
|
|
pubmed:issnType |
Print
|
|
pubmed:volume |
117
|
|
pubmed:owner |
NLM
|
|
pubmed:authorsComplete |
Y
|
|
pubmed:pagination |
408-13
|
|
pubmed:dateRevised |
2008-11-21
|
|
pubmed:meshHeading |
pubmed-meshheading:7608131-3-Isopropylmalate Dehydrogenase,
pubmed-meshheading:7608131-Alcohol Oxidoreductases,
pubmed-meshheading:7608131-Amino Acid Sequence,
pubmed-meshheading:7608131-Arginine,
pubmed-meshheading:7608131-Base Sequence,
pubmed-meshheading:7608131-Binding Sites,
pubmed-meshheading:7608131-Crystallography, X-Ray,
pubmed-meshheading:7608131-DNA Primers,
pubmed-meshheading:7608131-Enzyme Stability,
pubmed-meshheading:7608131-Hot Temperature,
pubmed-meshheading:7608131-Hydrogen Bonding,
pubmed-meshheading:7608131-Macromolecular Substances,
pubmed-meshheading:7608131-Models, Molecular,
pubmed-meshheading:7608131-Molecular Sequence Data,
pubmed-meshheading:7608131-Mutagenesis, Site-Directed,
pubmed-meshheading:7608131-Point Mutation,
pubmed-meshheading:7608131-Protein Structure, Secondary,
pubmed-meshheading:7608131-Recombinant Proteins,
pubmed-meshheading:7608131-Thermodynamics,
pubmed-meshheading:7608131-Thermus thermophilus
|
|
pubmed:year |
1995
|
|
pubmed:articleTitle |
The crystal structures of mutated 3-isopropylmalate dehydrogenase from Thermus thermophilus HB8 and their relationship to the thermostability of the enzyme.
|
|
pubmed:affiliation |
Department of Life Science, Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama.
|
|
pubmed:publicationType |
Journal Article,
Comparative Study
|
