tailieunhanh - Báo cáo khoa học: Identification and characterization of cytochrome bc1 subcomplexes in mitochondria from yeast with single and double deletions of genes encoding cytochrome bc1 subunits

We have examined the status of the cytochromebc1 complex in mitochon-drial membranes from yeast mutants in which genes for one or more of the cytochromebc1 complex subunits were deleted. When membranes from wild-type yeast were resolved by native gel electrophoresis and analyzed by immunodecoration, the cytochrome bc1 complex was detected as a mixed population of enzymes, consisting of cytochromebc1 dimers, and ternary complexes of cytochromebc1 dimers associated with one and two copies of the cytochrome c oxidase complex | ễFEBS Journal Identification and characterization of cytochrome bc1 subcomplexes in mitochondria from yeast with single and double deletions of genes encoding cytochrome bc1 subunits Vincenzo Zara1 Laura Conte1 and Bernard L. Trumpower2 1 Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali Universita delSalento Lecce Italy 2 Department of Biochemistry Dartmouth Medical School Hanover NH USA Keywords cytochrome bc1 assembly cytochrome bc1 complex cytochrome bc1 subcomplexes yeast deletion mutants yeast mitochondria Correspondence V. Zara Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali University delSalento Via Prov. le Lecce-Monteroni I-73100 Lecce Italy Fax 39 0832 298626 Tel 39 0832 298705 E-mail B. L. Trumpower Department of Biochemistry Dartmouth Medical School Hanover NH 03755 USA Fax 1 603 650 1389 Tel 1 603 650 1621 E-mail Trumpower@ Received 8 June 2007 revised 6 July 2007 accepted 10 July 2007 doi We have examined the status of the cytochrome bc1 complex in mitochondrial membranes from yeast mutants in which genes for one or more of the cytochrome bc1 complex subunits were deleted. When membranes from wild-type yeast were resolved by native gel electrophoresis and analyzed by immunodecoration the cytochrome bc1 complex was detected as a mixed population of enzymes consisting of cytochrome bc1 dimers and ternary complexes of cytochrome bc1 dimers associated with one and two copies of the cytochrome c oxidase complex. When membranes from the deletion mutants were resolved and analyzed the cytochrome bci dimer was not associated with the cytochrome c oxidase complex in many of the mutant membranes and membranes from some of the mutants contained a common set of cytochrome bci subcomplexes. When these subcomplexes were fractionated by SDS PAGE and analyzed with subunit-specific antibodies it was possible to recognize a subcomplex consisting of cytochrome b subunit 7 and