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...
Published in: | Journal of the American Chemical Society |
---|---|
Main Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
American Chemical Society
1988
|
Subjects: | |
Online Access: | https://authors.library.caltech.edu/24137/ https://authors.library.caltech.edu/24137/1/Axup_1988_J_Am_Chem_Soc_Distance_dependence_of_photoinduced_long-range.pdf https://resolver.caltech.edu/CaltechAUTHORS:20110620-160435945 |
id |
ftcaltechauth:oai:authors.library.caltech.edu:24137 |
---|---|
record_format |
openpolar |
spelling |
ftcaltechauth:oai:authors.library.caltech.edu:24137 2023-05-15T18:26:49+02:00 Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins Axup, Andrew W. Albin, Michael Mayo, Stephen L. Crutchley, Robert J. Gray, Harry B. 1988-01-20 application/pdf https://authors.library.caltech.edu/24137/ https://authors.library.caltech.edu/24137/1/Axup_1988_J_Am_Chem_Soc_Distance_dependence_of_photoinduced_long-range.pdf https://resolver.caltech.edu/CaltechAUTHORS:20110620-160435945 en eng American Chemical Society https://authors.library.caltech.edu/24137/1/Axup_1988_J_Am_Chem_Soc_Distance_dependence_of_photoinduced_long-range.pdf Axup, Andrew W. and Albin, Michael and Mayo, Stephen L. and Crutchley, Robert J. and Gray, Harry B. (1988) Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins. Journal of the American Chemical Society, 110 (2). pp. 435-439. ISSN 0002-7863. doi:10.1021/ja00210a020. https://resolver.caltech.edu/CaltechAUTHORS:20110620-160435945 <https://resolver.caltech.edu/CaltechAUTHORS:20110620-160435945> other Article PeerReviewed 1988 ftcaltechauth https://doi.org/10.1021/ja00210a020 2021-11-11T18:47:08Z 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) (a_5Ru;a = NH_3) derivatives of sperm whale myoglobin (Mb): a_5Ru(His-48)Mb, a_5Ru(His-12)Mb, a_5Ru(His-116)Mb, a_5Ru(His-81)Mb. Electron transfer from the ZnP triplet excited state (^3ZnP*) to Ru^3+, ^3ZnP*-Ru^3+ → ZnP^+-Ru^2+ (ΔE° ~ 0.8V) was measured by time-resolved transient absorption spectroscopy: rate constants (k_f) are 7.0 × 10^4 (His-48), 1.0 × 10^2 (His-12), 8.9 × 10^1 (His-116), and 8.5 × 10^1 (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 a_5Ru(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 k_f = 7.8 × 10^8 exp[-0.9l(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 Caltech Authors (California Institute of Technology) Journal of the American Chemical Society 110 2 435 439 |
institution |
Open Polar |
collection |
Caltech Authors (California Institute of Technology) |
op_collection_id |
ftcaltechauth |
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) (a_5Ru;a = NH_3) derivatives of sperm whale myoglobin (Mb): a_5Ru(His-48)Mb, a_5Ru(His-12)Mb, a_5Ru(His-116)Mb, a_5Ru(His-81)Mb. Electron transfer from the ZnP triplet excited state (^3ZnP*) to Ru^3+, ^3ZnP*-Ru^3+ → ZnP^+-Ru^2+ (ΔE° ~ 0.8V) was measured by time-resolved transient absorption spectroscopy: rate constants (k_f) are 7.0 × 10^4 (His-48), 1.0 × 10^2 (His-12), 8.9 × 10^1 (His-116), and 8.5 × 10^1 (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 a_5Ru(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 k_f = 7.8 × 10^8 exp[-0.9l(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, Andrew W. Albin, Michael Mayo, Stephen L. Crutchley, Robert J. Gray, Harry B. |
spellingShingle |
Axup, Andrew W. Albin, Michael Mayo, Stephen L. Crutchley, Robert J. Gray, Harry B. Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins |
author_facet |
Axup, Andrew W. Albin, Michael Mayo, Stephen L. Crutchley, Robert J. Gray, Harry B. |
author_sort |
Axup, 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 |
publisher |
American Chemical Society |
publishDate |
1988 |
url |
https://authors.library.caltech.edu/24137/ https://authors.library.caltech.edu/24137/1/Axup_1988_J_Am_Chem_Soc_Distance_dependence_of_photoinduced_long-range.pdf https://resolver.caltech.edu/CaltechAUTHORS:20110620-160435945 |
genre |
Sperm whale |
genre_facet |
Sperm whale |
op_relation |
https://authors.library.caltech.edu/24137/1/Axup_1988_J_Am_Chem_Soc_Distance_dependence_of_photoinduced_long-range.pdf Axup, Andrew W. and Albin, Michael and Mayo, Stephen L. and Crutchley, Robert J. and Gray, Harry B. (1988) Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins. Journal of the American Chemical Society, 110 (2). pp. 435-439. ISSN 0002-7863. doi:10.1021/ja00210a020. https://resolver.caltech.edu/CaltechAUTHORS:20110620-160435945 <https://resolver.caltech.edu/CaltechAUTHORS:20110620-160435945> |
op_rights |
other |
op_doi |
https://doi.org/10.1021/ja00210a020 |
container_title |
Journal of the American Chemical Society |
container_volume |
110 |
container_issue |
2 |
container_start_page |
435 |
op_container_end_page |
439 |
_version_ |
1766208788613824512 |