Linked Life Data

10832633

Source:http://linkedlifedata.com/resource/pubmed/id/10832633

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
2000-9-7
pubmed:databankReference
pubmed:abstractText
All Archaea catalyse the conversion of pyruvate to acetyl-CoA via a simple pyruvate oxidoreductase. This is in contrast to the Eukarya and most aerobic bacteria, which use the pyruvate dehydrogenase multienzyme complex [PDHC], consisting of multiple copies of three component enzymes: E1 (pyruvate decarboxylase), E2 (lipoate acetyl-transferase) and E3 (dihydrolipoamide dehydrogenase, DHLipDH). Until now no PDHC activity has been found in the Archaea, although DHLipDH has been discovered in the extremely halophilic Archaea and its gene sequence has been determined. In this paper, the discovery and sequencing of an operon containing the DHLipDH gene in the halophilic archaeon Haloferax volcanii are reported. Upstream of the DHLipDH gene are 3 ORFs which show highest sequence identities with the E1alpha, E1beta and E2 genes of the PDHC from gram-positive organisms. Structural predictions of the proposed protein product of the E2 gene show a domain structure characteristic of the E2 component in PDHCs, and catalytically important residues, including the lysine to which the lipoic acid cofactor is covalently bound, are conserved. Northern analyses indicate the transcription of the whole operon, but no PDHC enzymic activity could be detected in cell extracts. The presence in the E2 gene of an insertion (equivalent to approximately 100 aa) not found in bacterial or eukaryal E2 proteins, might be predicted to prevent multienzyme complex assembly. This is the first detailed report of the genes for a putative 2-oxoacid dehydrogenase complex in the Archaea, and the evolutionary and metabolic consequences of these findings are discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1350-0872
pubmed:author
pubmed:issnType
Print
pubmed:volume
146 ( Pt 5)
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1061-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
2-Oxoacid dehydrogenase multienzyme complexes in the halophilic Archaea? Gene sequences and protein structural predictions.
pubmed:affiliation
Centre for Extremophile Research, Department of Biology and Biochemistry, University of Bath, UK.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't