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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2005-1-4
pubmed:abstractText
Common structural motifs, such as the cupin domains, are found in enzymes performing different biochemical functions while retaining a similar active site configuration and structural scaffold. The soil bacterium Bacillus subtilis has 20 cupin genes (0.5% of the total genome) with up to 14% of its genes in the form of doublets, thus making it an attractive system for studying the effects of gene duplication. There are four bicupins in B. subtilis encoded by the genes yvrK, yoaN, yxaG, and ywfC. The gene products of yvrK and yoaN function as oxalate decarboxylases with a manganese ion at the active site(s), whereas YwfC is a bacitracin synthetase. Here we present the crystal structure of YxaG, a novel iron-containing quercetin 2,3-dioxygenase with one active site in each cupin domain. Yxag is a dimer, both in solution and in the crystal. The crystal structure shows that the coordination geometry of the Fe ion is different in the two active sites of YxaG. Replacement of the iron at the active site with other metal ions suggests modulation of enzymatic activity in accordance with the Irving-Williams observation on the stability of metal ion complexes. This observation, along with a comparison with the crystal structure of YvrK determined recently, has allowed for a detailed structure-function analysis of the active site, providing clues to the diversification of function in the bicupin family of proteins.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
11
pubmed:volume
44
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
193-201
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
The crystal structure of a quercetin 2,3-dioxygenase from Bacillus subtilis suggests modulation of enzyme activity by a change in the metal ion at the active site(s).
pubmed:affiliation
Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't