TY - JOUR
T1 - Perturbation of the CuA Site in Cytochrome‐c Oxidase of Paracoccus denitrificans by Replacement of Met227 with Isoleucine
AU - Zickermann, Volker
AU - Verkhovsky, Michael
AU - Morgan, Joel
AU - Wikström, Mårten
AU - Anemüller, Stefan
AU - Bill, Eckhard
AU - Steffens, Guy C.M.
AU - Ludwig, Bernd
N1 - Copyright:
Copyright 2016 Elsevier B.V., All rights reserved.
PY - 1995/12
Y1 - 1995/12
N2 - Subunit II of cytochrome‐c oxidase contains a redox centre, CuA, with unusual spectroscopic properties; this site consists of two copper atoms and acts as the entry point for electrons from cytochrome c. We have constructed a site–directed mutant of cytochrome‐c oxidase from Paracoccus denitrificans in which the CuA site has been disturbed by replacement of Met227 with isoleucine. The purified, fully assembled enzyme complex has been investigated with various techniques including metal analysis, EPR and visible spectroscopies, steady‐state and fast kinetics. The stoichiometry of the metals in the enzyme remains unchanged but a clear perturbation of the CuA site can be observed in the EPR and near‐infrared optical spectra. It is concluded that in the mutant CuA is still binuclear but that the two nuclei are no longer equivalent, converting the delocalized [Cu(1.5).…Cu(1.5)] centre of the wild type into a localized [Cu(I).…Cu(II)] system. Changes in the overall kinetics of the mutant are correlated with a diminished electron transfer rate between CuA and heme a.
AB - Subunit II of cytochrome‐c oxidase contains a redox centre, CuA, with unusual spectroscopic properties; this site consists of two copper atoms and acts as the entry point for electrons from cytochrome c. We have constructed a site–directed mutant of cytochrome‐c oxidase from Paracoccus denitrificans in which the CuA site has been disturbed by replacement of Met227 with isoleucine. The purified, fully assembled enzyme complex has been investigated with various techniques including metal analysis, EPR and visible spectroscopies, steady‐state and fast kinetics. The stoichiometry of the metals in the enzyme remains unchanged but a clear perturbation of the CuA site can be observed in the EPR and near‐infrared optical spectra. It is concluded that in the mutant CuA is still binuclear but that the two nuclei are no longer equivalent, converting the delocalized [Cu(1.5).…Cu(1.5)] centre of the wild type into a localized [Cu(I).…Cu(II)] system. Changes in the overall kinetics of the mutant are correlated with a diminished electron transfer rate between CuA and heme a.
UR - http://www.scopus.com/inward/record.url?scp=0028972745&partnerID=8YFLogxK
U2 - 10.1111/j.1432-1033.1995.686_b.x
DO - 10.1111/j.1432-1033.1995.686_b.x
M3 - Journal articles
C2 - 8536720
AN - SCOPUS:0028972745
SN - 0014-2956
VL - 234
SP - 686
EP - 693
JO - European Journal of Biochemistry
JF - European Journal of Biochemistry
IS - 2
ER -