Linked Life Data

14979714

Source:http://linkedlifedata.com/resource/pubmed/id/14979714

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2004-2-24
pubmed:databankReference
pubmed:abstractText
The topa quinone (TPQ) cofactor of copper amine oxidase is produced by posttranslational modification of a specific tyrosine residue through the copper-dependent, self-catalytic process. We have site-specifically mutated three histidine residues (His431, His433, and His592) involved in binding of the copper ion in the recombinant phenylethylamine oxidase from Arthrobacter globiformis. The mutant enzymes, in which each histidine was replaced by alanine, were purified in the Cu/TPQ-free precursor form and analyzed for their Cu-binding and TPQ-generating activities by UV-visible absorption, resonance Raman, and electron paramagnetic resonance spectroscopies. Among the three histidine-to-alanine mutants, only H592A was found to show a weak activity to form TPQ upon aerobic incubation with Cu(2+) ions. Also for H592A, exogenous imidazole rescued binding of copper and markedly promoted the TPQ formation. Accommodation of a free imidazole molecule within the cavity created in the active site of H592A was suggested by X-ray crystallography. Although the TPQ cofactor in H592A mutant was readily reduced with substrate, its catalytic activity was very low even in the presence of imidazole. Combined with the crystal structures of the mutant enzymes, these results demonstrate the importance of the three copper-binding histidine residues for both TPQ biogenesis and catalytic activity, fine-tuning the position of the essential metal.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
43
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2178-87
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Chemical rescue of a site-specific mutant of bacterial copper amine oxidase for generation of the topa quinone cofactor.
pubmed:affiliation
Department of Structural Molecular Biology, Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't