Linked Life Data

8718457

Source:http://linkedlifedata.com/resource/pubmed/id/8718457

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1996-10-11
pubmed:abstractText
Four mutations in the mitochondrial cytochrome b of S. cerevisiae have been characterized with respect to growth capacities, catalytic properties, ATP/2e- ratio, and transmembrane potential. The respiratory-deficient mutant G137E and the three pseudo-wild type revertants E137 + I147F, E137 + C133S, and E137 + N256K were described previously (Tron and Lemesle-Meunier, 1990; Di Rago et al., 1990a). The mutant G137E is unable to grow on respiratory substrates but its electron transfer activity is partly conserved and totally inhibited by antimycin A. The secondary mutations restore the respiratory growth at variable degree, with a phosphorylation efficiency of 12-42% as regards the parental wild type strain, and result in a slight increase in the various electron transfer activities at the level of the whole respiratory chain. The catalytic efficiency for ubiquinol was slightly (G137E) or not affected (E137 + I147F, E137 + C133S, and E137 + N256K) in these mutants. Mutation G137E induces a decrease in the ATP/2e- ratio (50% of the W.T. value) and transmembrane potential (60% of the W.T. value) at the bc1 level, whereas the energetic capacity of the cytochrome oxidase is conserved. Secondary mutations I147F, C133S, and N256K partly restore the ATP/2e- ratio and the transmembrane potential at the bc1 complex level. The results suggest that a partial decoupling of the bc1 complex is induced by the cytochrome b point mutation G137E. In the framework of the protonmotive Q cycle, this decoupling can be explained by the existence of a proton wire connecting centers P and N in the wild type bc1 complex which may be amplified or uncovered by the G137E mutation when the bc1 complex is functioning.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0145-479X
pubmed:author
pubmed:issnType
Print
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
527-39
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Decoupling of the bc1 complex in S. cerevisiae; point mutations affecting the cytochrome b gene bring new information about the structural aspect of the proton translocation.
pubmed:affiliation
Laboratoire de Bioénergétique et Ingénierie des Protéines, C.N.R.S., Marseille, France.
pubmed:publicationType
Journal Article