The binding domain on horse cytochrome c and Rhodobacter sphaeroides cytochrome c2 for the Rhodobacter sphaeroides cytochrome bc1 complex

Biochemistry ◽  
1987 ◽  
Vol 26 (14) ◽  
pp. 4501-4504 ◽  
Author(s):  
Joan Hall ◽  
Xiaohui Zha ◽  
Linda Yu ◽  
Chang An Yu ◽  
Francis Millett
Keyword(s):  
Cytochrome C ◽  
Rhodobacter Sphaeroides ◽  
Binding Domain ◽  
Cytochrome Bc1 ◽  
Bc1 Complex ◽  
Cytochrome Bc1 Complex ◽  
Cytochrome C2 ◽  
Horse Cytochrome

Role of specific lysine residues in the reaction of Rhodobacter sphaeroides cytochrome c2 with the cytochrome bc1 complex

Biochemistry ◽  
1989 ◽  
Vol 28 (6) ◽  
pp. 2568-2571 ◽  
Author(s):  
Joan Hall ◽  
Xiaohui Zha ◽  
Linda Yu ◽  
Chang An Yu ◽  
Francis Millett
Keyword(s):  
Rhodobacter Sphaeroides ◽  
Cytochrome Bc1 ◽  
Bc1 Complex ◽  
Cytochrome Bc1 Complex ◽  
Cytochrome C2 ◽  
Lysine Residues

scholarly journals Topological organization of the Rieske iron-sulphur protein and subunit IV in the cytochrome bc1 complex of Rhodobacter sphaeroides

1995 ◽  
Vol 305 (3) ◽  
pp. 823-828 ◽  
Author(s):  
J Wu ◽  
R A Niederman
Keyword(s):  
Rhodobacter Sphaeroides ◽  
Transmembrane Domain ◽  
Transmembrane Helix ◽  
Proteinase K ◽  
Cytochrome Bc1 ◽  
Bc1 Complex ◽  
Cytochrome Bc1 Complex ◽  
Intracytoplasmic Membrane ◽  
Cytochrome C2 ◽  
Cytochrome C1

The ubiquinol-cytochrome c2 oxidoreductases (cytochrome bc1 complex) of Rhodobacter sphaeroides contains highly conserved cytochrome b, cytochrome c1 and Rieske FeS subunits, as well as a unique 14 kDa polypeptide, designated as subunit IV, thought to function as a ubiquinol-binding protein [Yu and Yu (1991) Biochemistry 30, 4934-4939]. As the topology of subunit IV is unknown and that of the FeS subunit remains a matter of debate, both the inner (cytoplasmic) and outer (periplasmic) surfaces of the intracytoplasmic membrane (ICM) were digested with proteinase K, and cleavage products were identified by immunoblotting. In uniformly oriented chromatophore vesicles (inner ICM surface exposed), fragments of approx. 4 and 1 kDa were removed from subunit IV and the FeS protein respectively. Neither subunit IV nor the FeS protein was cleaved from the outer ICM surface as exposed in osmotically protected spheroplasts or as presented to proteinase K after microencapsulation of the protease in unilamellar liposomes and fusion of these structures to chromatophore vesicles. Studies with the isolated bc1 complex, however, suggested that the C-terminal domain of the Rieske FeS, thought to reside on the periplasmic side of the ICM, was resistant to proteinase K. Overall, these results suggest a single N-terminal transmembrane helix for the FeS protein, with exposure of the N-terminus to the cytoplasm and an orientation in which a major, N-terminal portion of subunit IV is located in the cytoplasm with the predicted C-terminal transmembrane domain anchoring this polypeptide to the membrane.

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