Linked Life Data

19381469

Source:http://linkedlifedata.com/resource/pubmed/id/19381469

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2009-4-21
pubmed:abstractText
Acetohydroxy-acid synthases (AHAS) of two mutant strains Streptomyces cinnamonensis ACB-NLR-2 and BVR-18 were chosen for this study for their apparent activation by valine, which regularly acts as an allosteric inhibitor. Sequencing the ilvB genes coding for the AHAS catalytic subunit revealed two distant changes in the mutants, DeltaQ217 and E139A, respectively. Homology modeling was used to propose the structural changes caused by those mutations. In the mutant strain ACB-NLR-2 (resistant to 2-amino-3-chlorobutyrate and norleucine), deletion of Q217 affected a helix in ss-domain, distant from the active center. As no mutation was found in the regulatory subunit of this strain, DeltaQ217 in IlvB was supposed to be responsible for the observed valine activation, probably via changed properties on the proposed regulatory-catalytic subunit interface. In mutant strain BVR-18 (resistant to 2-oxobutyrate), substitution E139A occurred in a conservative loop near the active center. In vitro AHAS activity assay with the enzyme reconstituted from the wild-type regulatory and BVR-18 catalytic subunits proved that the substitution in the catalytic subunit led to the apparent activation of AHAS by valine. We suggest that the conservative loop participated in a conformational change transfer to the active center during the allosteric regulation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
1874-9356
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
53
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
467-71
pubmed:dateRevised
2009-9-1
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Deregulation of acetohydroxy-acid synthase: Loss of allosteric inhibition conferred by mutations in the catalytic subunit.
pubmed:affiliation
Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic. jkopecky@vurv.cz
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't