TY - JOUR
T1 - Long-Range Electron Transfer at Fixed and Known Distance within Protein Complexes
AU - Peterson-Kennedy, S. E.
AU - McGourty, J. L.
AU - Ho, P. S.
AU - Sutoris, C. J.
AU - Liang, N.
AU - Zemel, H.
AU - Blough, N. V.
AU - Margoliash, E.
AU - Hoffman, B. M.
N1 - Funding Information:
This work has been supported by NIH Grant HL13531'and NSF Grant PCM 76-81304. It has been encouraged by stimulating discussions with H.B. Gray, S. Iseid, G. McLendon, J. Miller, M.A. Ratner, and R.P. Van Duyne.
PY - 1985/5
Y1 - 1985/5
N2 - We have used zinc-substituted hemoproteins to study long-range electron transfer between redox centers at fixed and known distances. The photo-excited zinc triplet state in one subunit of the α1-β2 electron transfer complex of [Zn,Fe] hybrid hemoglobin transfers an electron to its partner aquoferriheme subunit at a rate, kt=100 s-1. The temperature dependence of this electron transfer from 77K to 313K is indicative of non-adiabatic electron tunnelling in which the accompanying nuclear rearrangements proceed by nuclear tunnelling. For the complex between zinc-substituted yeast cytochrome c peroxidase (CCP) and native yeast cytochrome c, electron transfer occurs at a rate, kt=138 s-1, compared to kt = 17 s-1 in the complex between the yeast enzyme and horse cyt c. The difference demonstrates the species specificity involved in physiological electron transfer. Oxidation of ferroporphyrin by the zinc porphyrin radical is more rapid, and, for the yeast cytochrome, occurs with a rate, kh ∼ 104 s-1.
AB - We have used zinc-substituted hemoproteins to study long-range electron transfer between redox centers at fixed and known distances. The photo-excited zinc triplet state in one subunit of the α1-β2 electron transfer complex of [Zn,Fe] hybrid hemoglobin transfers an electron to its partner aquoferriheme subunit at a rate, kt=100 s-1. The temperature dependence of this electron transfer from 77K to 313K is indicative of non-adiabatic electron tunnelling in which the accompanying nuclear rearrangements proceed by nuclear tunnelling. For the complex between zinc-substituted yeast cytochrome c peroxidase (CCP) and native yeast cytochrome c, electron transfer occurs at a rate, kt=138 s-1, compared to kt = 17 s-1 in the complex between the yeast enzyme and horse cyt c. The difference demonstrates the species specificity involved in physiological electron transfer. Oxidation of ferroporphyrin by the zinc porphyrin radical is more rapid, and, for the yeast cytochrome, occurs with a rate, kh ∼ 104 s-1.
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U2 - 10.1016/0010-8545(85)80046-1
DO - 10.1016/0010-8545(85)80046-1
M3 - Article
AN - SCOPUS:0011165145
VL - 64
SP - 125
EP - 133
JO - Coordination Chemistry Reviews
JF - Coordination Chemistry Reviews
SN - 0010-8545
IS - C
ER -