Linked Life Data

19021513

Source:http://linkedlifedata.com/resource/pubmed/id/19021513

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
Pt 6
pubmed:dateCreated
2008-11-21
pubmed:abstractText
The metabolic flexibility of bacteria is key to their ability to survive and thrive in a wide range of environments. Optimal switching from one metabolic pathway to another is a key requirement for this flexibility. Respiration is a good example: many bacteria utilize O(2) as the terminal electron acceptor, but can switch to a range of other acceptors, such as nitrate, when O(2) becomes limiting. Sensing environmental levels of O(2) is the key step in switching from aerobic to anaerobic respiration. In Escherichia coli, the fumarate and nitrate reduction transcriptional regulator (FNR) controls this switch. Under O(2)-limiting conditions, FNR binds a [4Fe-4S](2+) cluster, generating a transcriptionally active dimeric form. Exposure to O(2) results in conversion of the cluster into a [2Fe-2S](2+) form, leading to dissociation of the protein into inactive monomers. The mechanism of cluster conversion, together with the nature of the reaction products, is of considerable current interest, and a near-complete description of the process has now emerged. The [4Fe-4S](2+) into [2Fe-2S](2+) cluster conversion proceeds via a two-step mechanism. In step 1, a one-electron oxidation of the cluster takes place, resulting in the release of a Fe(2+) ion, the formation of an intermediate [3Fe-4S](1+) cluster, together with the generation of a superoxide anion. In step 2, the intermediate [3Fe-4S](1+) cluster rearranges spontaneously to form the [2Fe-2S](2+) cluster, releasing two sulfide ions and an Fe(3+) ion in the process. The one-electron activation of the cluster, coupled to catalytic recycling of the superoxide anion back to oxygen via superoxide dismutase and catalase, provides a novel means of amplifying the sensitivity of [4Fe-4S](2+) FNR to its signal molecule.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1470-8752
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1144-8
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Signal perception by FNR: the role of the iron-sulfur cluster.
pubmed:affiliation
Centre for Molecular and Structural Biochemistry, School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, UK. J.Crack@uea.ac.uk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't