Linked Life Data

21441514

Source:http://linkedlifedata.com/resource/pubmed/id/21441514

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2011-4-29
pubmed:abstractText
The membrane-bound [NiFe] hydrogenase (MBH) of Ralstonia eutropha H16 undergoes a complex maturation process comprising cofactor assembly and incorporation, subunit oligomerization, and finally twin-arginine-dependent membrane translocation. Due to its outstanding O(2) and CO tolerance, the MBH is of biotechnological interest and serves as a molecular model for a robust hydrogen catalyst. Adaptation of the enzyme to oxygen exposure has to take into account not only the catalytic reaction but also biosynthesis of the intricate redox cofactors. Here, we report on the role of the MBH-specific accessory proteins HoxR and HoxT, which are key components in MBH maturation at ambient O(2) levels. MBH-driven growth on H(2) is inhibited or retarded at high O(2) partial pressure (pO(2)) in mutants inactivated in the hoxR and hoxT genes. The ratio of mature and nonmature forms of the MBH small subunit is shifted toward the precursor form in extracts derived from the mutant cells grown at high pO(2). Lack of hoxR and hoxT can phenotypically be restored by providing O(2)-limited growth conditions. Analysis of copurified maturation intermediates leads to the conclusion that the HoxR protein is a constituent of a large transient protein complex, whereas the HoxT protein appears to function at a final stage of MBH maturation. UV-visible spectroscopy of heterodimeric MBH purified from hoxR mutant cells points to alterations of the Fe-S cluster composition. Thus, HoxR may play a role in establishing a specific Fe-S cluster profile, whereas the HoxT protein seems to be beneficial for cofactor stability under aerobic conditions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1098-5530
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
193
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2487-97
pubmed:dateRevised
2011-11-1
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
The maturation factors HoxR and HoxT contribute to oxygen tolerance of membrane-bound [NiFe] hydrogenase in Ralstonia eutropha H16.
pubmed:affiliation
Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestrasse 117, 10115 Berlin, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't