Linked Life Data

12743680

Source:http://linkedlifedata.com/resource/pubmed/id/12743680

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2003-5-29
pubmed:abstractText
In autotrophic methanogens, pyruvate oxidoreductase (POR) plays a key role in the assimilation of CO(2) and the biosynthesis of organic carbon. This enzyme has been purified to homogeneity, and the genes from Methanococcus maripaludis were sequenced. The purified POR contained five polypeptides with molecular masses of 47, 33, 25, 21.5 and 13 kDa. The N-terminal sequences of four of the polypeptides had high similarity to the subunits commonly associated with this enzyme from other archaea. However, the 21.5-kDa polypeptide had not been previously observed in PORs. Nucleotide sequencing of the gene cluster encoding the POR revealed six open reading frames ( porABCDEF). The genes porABCD corresponded to the subunits previously identified in PORs. On the basis of the N-terminal amino acid sequence, porE encoded the 21.5-kDa polypeptide and contained a high cysteinyl residue content and a motif indicative of a [Fe-S] cluster. porF also had a high sequence similarity to porE, a high cysteinyl residue content, and two [Fe-S] cluster motifs. Homologs to porE were also present in the genomic sequences of the autotrophic methanogens Methanocaldococcus jannaschii and Methanothermobacter thermautotrophicus. Based upon these results, it is proposed that PorE and PorF are components of a specialized system required to transfer low-potential electrons for pyruvate biosynthesis. Some biochemical properties of the purified methanococcal POR were also determined. This unstable enzyme was very sensitive to O(2 )and demonstrated high activity with pyruvate, oxaloacetate, and alpha-ketobutyrate. Methyl viologen, rubredoxin, FMN, and FAD were readily reduced. Activity was also observed with spinach and clostridial ferredoxins and cytochrome c. Coenzyme F(420) was not an electron acceptor for the purified enzyme.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0302-8933
pubmed:author
pubmed:issnType
Print
pubmed:volume
179
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
444-56
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
The anabolic pyruvate oxidoreductase from Methanococcus maripaludis.
pubmed:affiliation
Department of Microbiology, University of Georgia, Athens, GA 30602-2605, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.