Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins
An experimental investigation of the distance dependence of long-range electron transfer in zinc/ruthenium-modified myoglobins has been performed. The modified proteins were prepared by substitution of zinc mesoporphyrin IX diacid (ZnP) for the heme in each of four previously characterized pentaammi...
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ftcarletonunivir:oai:carleton.ca:928 2023-05-15T18:26:48+02:00 Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins Axup, A.W. (Andrew W.) Albin, M. (Michael) Mayo, S.L. (Stephen L.) Crutchley, R. (Robert) Gray, H.B. (Harry B.) 1988-01-01 https://ir.library.carleton.ca/pub/928 en eng https://ir.library.carleton.ca/pub/928 American Chemical Society Journal vol. 110 no. 2, pp. 435-439 info:eu-repo/semantics/article 1988 ftcarletonunivir 2022-02-06T21:49:58Z An experimental investigation of the distance dependence of long-range electron transfer in zinc/ruthenium-modified myoglobins has been performed. The modified proteins were prepared by substitution of zinc mesoporphyrin IX diacid (ZnP) for the heme in each of four previously characterized pentaammineruthenium(III) (a5Ru; a = NH3) derivatives of sperm whale myoglobin (Mb): a5Ru(His-48)Mb, a5Ru(His-12)Mb, a5Ru(His-116)Mb, a5Ru(His-81)Mb. Electron transfer from the ZnP triplet excited state (3ZnP*) to Ru3+, 3ZnP*-Ru3+ → ZnP+-Ru2+ (ΔE° ∼ 0.8 V) was measured by time-resolved transient absorption spectroscopy: rate constants (kf) are 7.0 × 104 (His-48), 1.0 × 102 (His-12), 8.9 × 101 (His-116), and 8.5 × 101 (His-81) s-1 at 25°C. Activation enthalpies calculated from the temperature dependences of the electron-transfer rates over the range 5-40°C are 1.7 ± 1.6 (His-48), 4.7 ± 0.9 (His-12), 5.4 ± 0.4 (His-116), and 5.6 ± 2.5 (His-81) kcal mol-1. Electron-transfer distances (d = closest ZnP edge to ȧ5Ru(His) edge; angstroms) were calculated to fall in the following ranges: His-48, 11.8-16.6; His-12, 21.5-22.3; His-116, 19.8-20.4; His-81, 18.8-19.3. The rate-distance equation is kf = 7.8 × 108 exp[-0.91(d- 3)] s-1. The data indicate that the 3ZnP*-Ru(His-12)3+ electronic coupling may be enhanced by an intervening tryptophan (Trp-14). Article in Journal/Newspaper Sperm whale Carleton University's Institutional Repository |
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Carleton University's Institutional Repository |
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ftcarletonunivir |
language |
English |
description |
An experimental investigation of the distance dependence of long-range electron transfer in zinc/ruthenium-modified myoglobins has been performed. The modified proteins were prepared by substitution of zinc mesoporphyrin IX diacid (ZnP) for the heme in each of four previously characterized pentaammineruthenium(III) (a5Ru; a = NH3) derivatives of sperm whale myoglobin (Mb): a5Ru(His-48)Mb, a5Ru(His-12)Mb, a5Ru(His-116)Mb, a5Ru(His-81)Mb. Electron transfer from the ZnP triplet excited state (3ZnP*) to Ru3+, 3ZnP*-Ru3+ → ZnP+-Ru2+ (ΔE° ∼ 0.8 V) was measured by time-resolved transient absorption spectroscopy: rate constants (kf) are 7.0 × 104 (His-48), 1.0 × 102 (His-12), 8.9 × 101 (His-116), and 8.5 × 101 (His-81) s-1 at 25°C. Activation enthalpies calculated from the temperature dependences of the electron-transfer rates over the range 5-40°C are 1.7 ± 1.6 (His-48), 4.7 ± 0.9 (His-12), 5.4 ± 0.4 (His-116), and 5.6 ± 2.5 (His-81) kcal mol-1. Electron-transfer distances (d = closest ZnP edge to ȧ5Ru(His) edge; angstroms) were calculated to fall in the following ranges: His-48, 11.8-16.6; His-12, 21.5-22.3; His-116, 19.8-20.4; His-81, 18.8-19.3. The rate-distance equation is kf = 7.8 × 108 exp[-0.91(d- 3)] s-1. The data indicate that the 3ZnP*-Ru(His-12)3+ electronic coupling may be enhanced by an intervening tryptophan (Trp-14). |
format |
Article in Journal/Newspaper |
author |
Axup, A.W. (Andrew W.) Albin, M. (Michael) Mayo, S.L. (Stephen L.) Crutchley, R. (Robert) Gray, H.B. (Harry B.) |
spellingShingle |
Axup, A.W. (Andrew W.) Albin, M. (Michael) Mayo, S.L. (Stephen L.) Crutchley, R. (Robert) Gray, H.B. (Harry B.) Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins |
author_facet |
Axup, A.W. (Andrew W.) Albin, M. (Michael) Mayo, S.L. (Stephen L.) Crutchley, R. (Robert) Gray, H.B. (Harry B.) |
author_sort |
Axup, A.W. (Andrew W.) |
title |
Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins |
title_short |
Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins |
title_full |
Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins |
title_fullStr |
Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins |
title_full_unstemmed |
Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins |
title_sort |
distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins |
publishDate |
1988 |
url |
https://ir.library.carleton.ca/pub/928 |
genre |
Sperm whale |
genre_facet |
Sperm whale |
op_source |
American Chemical Society Journal vol. 110 no. 2, pp. 435-439 |
op_relation |
https://ir.library.carleton.ca/pub/928 |
_version_ |
1766208775655522304 |