{"database":"biostudies-other","file_versions":[],"scores":null,"additional":{"omics_type":["Unknown"],"volume":["247(2)"],"submitter":["Alleyne TA"],"journal":["The Biochemical journal"],"pagination":["475-84"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC1148432"],"abstract":["Zinc cytochrome c forms tight 1:1 complexes with a variety of derivatives of cytochrome c oxidase. On complex-formation the fluorescence of zinc cytochrome c is diminished. Titrations of zinc cytochrome c with cytochrome c oxidase, followed through the fluorescence emission of the former, have yielded both binding constants (K approximately 7 x 10(6) M-1 for the fully oxidized and 2 x 10(7) M-1 for the fully reduced enzyme) and distance information. Comparison of steady-state measurements obtained by absorbance and fluorescence spectroscopy in the presence and in the absence of cyanide show that it is the reduction of cytochrome a and/or CuA that triggers a conformational change: this increases the zinc cytochrome c to acceptor (most probably cytochrome a itself) distance by some 0.5 nm. Ligand binding to the fully oxidized or fully reduced enzyme leaves the extent of fluorescence quenching unchanged, whereas binding of cyanide to the half-reduced enzyme (a2+CuA+CuB2+-CN(-)-a3(3+)) enhances fluorescence emission relative to that for the fully reduced enzyme, implying further relative movement of donor and acceptor."],"repository":["biostudies-other"],"data_source":["Europe PMC"],"pubmed_authors":["Wilson MT","Alleyne TA"],"additional_accession":[]},"is_claimable":false,"name":"Zinc cytochrome c fluorescence as a probe for conformational changes in cytochrome c oxidase.","description":"Zinc cytochrome c forms tight 1:1 complexes with a variety of derivatives of cytochrome c oxidase. On complex-formation the fluorescence of zinc cytochrome c is diminished. Titrations of zinc cytochrome c with cytochrome c oxidase, followed through the fluorescence emission of the former, have yielded both binding constants (K approximately 7 x 10(6) M-1 for the fully oxidized and 2 x 10(7) M-1 for the fully reduced enzyme) and distance information. Comparison of steady-state measurements obtained by absorbance and fluorescence spectroscopy in the presence and in the absence of cyanide show that it is the reduction of cytochrome a and/or CuA that triggers a conformational change: this increases the zinc cytochrome c to acceptor (most probably cytochrome a itself) distance by some 0.5 nm. Ligand binding to the fully oxidized or fully reduced enzyme leaves the extent of fluorescence quenching unchanged, whereas binding of cyanide to the half-reduced enzyme (a2+CuA+CuB2+-CN(-)-a3(3+)) enhances fluorescence emission relative to that for the fully reduced enzyme, implying further relative movement of donor and acceptor.","dates":{"release":"1987-01-01T00:00:00Z","publication":"1987 Oct","modification":"2019-08-04T07:19:01Z","creation":"2019-08-04T07:19:01Z"},"accession":"S-EPMC1148432","cross_references":{"DOI":["10.1042/bj2470475 "]}}