TOPOLOGICAL ORGANIZATION OF SUBUNIT-VII AND SUBUNIT-VIII IN THE UBIQUINOL-CYTOCHROME-C OXIDOREDUCTASE OF SACCHAROMYCES-CEREVISIAE

Citation
H. Boumans et al., TOPOLOGICAL ORGANIZATION OF SUBUNIT-VII AND SUBUNIT-VIII IN THE UBIQUINOL-CYTOCHROME-C OXIDOREDUCTASE OF SACCHAROMYCES-CEREVISIAE, FEBS letters, 390(2), 1996, pp. 137-141
Citations number
37
Categorie Soggetti
Biophysics,Biology
Journal title
ISSN journal
00145793
Volume
390
Issue
2
Year of publication
1996
Pages
137 - 141
Database
ISI
SICI code
0014-5793(1996)390:2<137:TOOSAS>2.0.ZU;2-Q
Abstract
To determine the topology of subunit Vm of the yeast ubiquinol-cytochr ome c oxidoreductase in the mitochondrial inner membrane, an epitope h as been introduced in the N-terminal half of this protein, Previous to pology studies had shown that at least the C-terminus faces the interm embrane space [Hemrika and Berden (1990) fur. J, Biochem. 192, 761-765 ]., Based on sensitivity of the protein to proteinase K digestion we n ow suggest that the N-terminus of subunit VIII is similarly oriented, implying that this subunit does not span the membrane, Despite this, h owever, subunit VIII cannot be extracted from the membrane even after treatment with 0.1 M Na2CO3 at pH 11.5, showing that the protein is in tegrally embedded in the membrane, A similar behaviour was displayed b y another low molecular weight protein of the complex, subunit VII, wh ich faces the matrix side, A model for the topology of these subunits in the membrane is discussed with respect to the structure of the comp lex and their involvement in quinone binding.