Linked Life Data

11069658

Source:http://linkedlifedata.com/resource/pubmed/id/11069658

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2000-12-12
pubmed:abstractText
Archaeoglobus fulgidus is a hyperthermophilic sulphate-reducing archaeon. It has an optimum growth temperature of 83 degrees C and is described as a strict anaerobe. Its genome lacks any homologue of canonical superoxide (O2.-) dismutases. In this work, we show that neelaredoxin (Nlr) is the main O2.- scavenger in A. fulgidus, by studying both the wild-type and recombinant proteins. Nlr is a 125-amino-acid blue-coloured protein containing a single iron atom/molecule, which in the oxidized state is high spin ferric. This iron centre has a reduction potential of +230 mV at pH 7.0. Nitroblue tetrazolium-stained gel assays of cell-soluble extracts show that Nlr is the main protein from A. fulgidus which is reactive towards O2.-. Furthermore, it is shown that Nlr is able to both reduce and dismutate O2.-, thus having a bifunctional reactivity towards O2.-. Kinetic and spectroscopic studies indicate that Nlr's superoxide reductase activity may allow the cell to eliminate O2.- quickly in a NAD(P)H-dependent pathway. On the other hand, Nlr's superoxide dismutation activity will allow the cell to detoxify O2.- independently of the cell redox status. Its superoxide dismutase activity was estimated to be 59 U mg-1 by the xanthine/xanthine oxidase assay at 25 degrees C. Pulse radiolysis studies with the isolated and reduced Nlr proved unambiguously that it has superoxide dismutase activity; at pH 7.1 and 83 degrees C, the rate constant is 5 x 106 M-1 s-1. Besides the superoxide dismutase activity, soluble cell extracts of A. fulgidus also exhibit catalase and NAD(P)H/oxygen oxidoreductase activities. By putting these findings together with the entire genomic data available, a possible oxygen detoxification mechanism in A. fulgidus is discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
322-34
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Oxygen detoxification in the strict anaerobic archaeon Archaeoglobus fulgidus: superoxide scavenging by neelaredoxin.
pubmed:affiliation
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't