Linked Life Data

9872412

Source:http://linkedlifedata.com/resource/pubmed/id/9872412

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1999-1-25
pubmed:abstractText
The redox potential of the Rieske Fe-S protein has been investigated using circular dichroism (CD)-spectroscopy. The CD features characteristic of the purified bc1 complex and membranes of Rhodobacter sphaeroides were found in the region between 450 and 550 nm. The difference between reduced and oxidized CD-spectra shows a negative band at about 500 nm with a half of width 30 nm that corresponds to the specific dichroic absorption of the reduced Rieske protein (Fee, J.A. et al. (1984) J. Biol. Chem. 259, 124-133; Degli Esposti, M. et al. (1987) Biochem. J. 241, 285-290; Rich, P.R. and Wiggins, T.E. (1992) Biochem. Soc. Trans. 20, 241S). It was found that the redox potential at pH 7.0 for the Rieske center in the isolated bc1 complex and in chromatophore membranes from the R-26 strain of Rh. sphaeroides is 300 +/- 5 mV. In chromatophores from the BC17C strain of Rh. sphaeroides, the Em value measured for the Rieske iron-sulfur protein (ISP) was higher (315 +/- 5 mV), but the presence of carotenoids made measurement less accurate. The Em varied with pH in the range above pH 7, and the pH dependence was well fit either by one pK at approximately 7.5 in the range of titration, or by two pK values, pK1 = 7.6 and pK2 = 9.8. Similar titrations and pK values were found for the Rieske Fe-S protein in the isolated bc1 complex and membranes from the R-26 strain of Rb. sphaeroides. The results are discussed in the context of the mechanism of quinol oxidation by the bc1 complex, and the role of the iron sulfur protein in formation of a reaction complex at the Qo-site.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0014-5793
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
440
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
409-13
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
CD-monitored redox titration of the Rieske Fe-S protein of Rhodobacter sphaeroides: pH dependence of the midpoint potential in isolated bc1 complex and in membranes.
pubmed:affiliation
Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana 61801, USA. ugulava@uiuc.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.