Structural and functional characteristics of subunits of bovine heart cytochrome-c reductase have been investigated by controlled digestion of soluble and membrane-reconstituted purified bc1 complex and direct amino acid sequencing of native and digested protein subunits. The results obtained show that the N-terminal segments of core protein II and the 14-kDa protein extend at the periphery of the complex, protruding into the inner matrix space. The Fe-S protein, located at the outer C-periphery of the complex, is shown to be anchored to other subunits of the complex by the amphipathic N-terminal region. Proteolytic cleavage of 7-11 residues from the N-terminal segment of the 14-kDa protein is apparently associated with decoupling of redox-linked proton pumping. Partial digestion of core protein II, the 6.4-kDa protein, and the C-terminal region of the 9.2-kDa protein, is without effect on the redox and proton-motive activity of the complex.

Structural and functional characteristics of polypeptide subunits of the bovine heart ubiquinol-cytochrome-c reductase complex / T. Cocco, M. Lorusso, A. M. Sardanelli, M. Minuto, S. Ronchi, G. Tedeschi, S. Papa. - In: EUROPEAN JOURNAL OF BIOCHEMISTRY. - ISSN 0014-2956. - 195:3(1991), pp. 731-734.

Structural and functional characteristics of polypeptide subunits of the bovine heart ubiquinol-cytochrome-c reductase complex

S. Ronchi;G. Tedeschi
Penultimo
;
S. Papa
Ultimo
1991

Abstract

Structural and functional characteristics of subunits of bovine heart cytochrome-c reductase have been investigated by controlled digestion of soluble and membrane-reconstituted purified bc1 complex and direct amino acid sequencing of native and digested protein subunits. The results obtained show that the N-terminal segments of core protein II and the 14-kDa protein extend at the periphery of the complex, protruding into the inner matrix space. The Fe-S protein, located at the outer C-periphery of the complex, is shown to be anchored to other subunits of the complex by the amphipathic N-terminal region. Proteolytic cleavage of 7-11 residues from the N-terminal segment of the 14-kDa protein is apparently associated with decoupling of redox-linked proton pumping. Partial digestion of core protein II, the 6.4-kDa protein, and the C-terminal region of the 9.2-kDa protein, is without effect on the redox and proton-motive activity of the complex.
Settore BIO/10 - Biochimica
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/180706
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