TY - JOUR
T1 - On the environment of zinc in beef heart cytochrome c oxidase
T2 - an x-ray absorption study.
AU - Naqui, A.
AU - Powers, L.
AU - Lundeen, M.
AU - Constantinescu, A.
AU - Chance, B.
PY - 1988
Y1 - 1988
N2 - The role of zinc in beef heart cytochrome c oxidase has been studied by using x-ray absorption spectroscopy, zinc depletion and secondary structure predictions of subunits of beef heart cytochrome c oxidase. The stoichiometry of zinc in cytochrome oxidase has been determined in 35 different preparations and found to be one-half of copper (Cu:Zu = 2:1). Zinc is tightly bound to this enzyme and cannot be removed by dialysis against EDTA. However, zinc could be partially (up to 50%) depleted by treating the enzyme with either dipicolinic acid or by trypsin digestion. This partial depletion of zinc does not change the O2 uptake rate. X-ray absorption spectroscopy shows that the atom is in a distorted tetrahedral environment with mostly sulfur ligands. Since subunit VIa removed by the digestion removes about one-half the zinc, a possible binding site involves the two S sites present in that subunit with an appropriate folding in a structural role.
AB - The role of zinc in beef heart cytochrome c oxidase has been studied by using x-ray absorption spectroscopy, zinc depletion and secondary structure predictions of subunits of beef heart cytochrome c oxidase. The stoichiometry of zinc in cytochrome oxidase has been determined in 35 different preparations and found to be one-half of copper (Cu:Zu = 2:1). Zinc is tightly bound to this enzyme and cannot be removed by dialysis against EDTA. However, zinc could be partially (up to 50%) depleted by treating the enzyme with either dipicolinic acid or by trypsin digestion. This partial depletion of zinc does not change the O2 uptake rate. X-ray absorption spectroscopy shows that the atom is in a distorted tetrahedral environment with mostly sulfur ligands. Since subunit VIa removed by the digestion removes about one-half the zinc, a possible binding site involves the two S sites present in that subunit with an appropriate folding in a structural role.
UR - https://www.scopus.com/pages/publications/0024279166
UR - https://www.scopus.com/pages/publications/0024279166#tab=citedBy
U2 - 10.1016/s0021-9258(18)37760-3
DO - 10.1016/s0021-9258(18)37760-3
M3 - Article
C2 - 2842329
AN - SCOPUS:0024279166
SN - 0021-9258
VL - 263
SP - 12342
EP - 12345
JO - The Journal of biological chemistry
JF - The Journal of biological chemistry
IS - 25
ER -