Polarized X-ray absorption spectroscopy of the low-temperature photoproduct of carbonmonoxy-myoglobin
Visible light can break the Fe—CO bond in Fe(II) carbonmonoxy-myoglobin (MbCO) giving an unligated product (Mb*) that is almost stable at T < 30 K. Fe K-edge polarized X-ray absorption spectra (P-XAS) of the photoproduct (T = 20 K) of an oriented single crystal (0.2 × 0.2 × 0.3 mm) of sperm whale...
Published in: | Journal of Synchrotron Radiation |
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Online Access: | https://www.openaccessrepository.it/record/102045 https://doi.org/10.1107/s0909049599010845 |
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ftopenaccessrep:oai:zenodo.org:102045 2023-10-25T01:44:08+02:00 Polarized X-ray absorption spectroscopy of the low-temperature photoproduct of carbonmonoxy-myoglobin Richard Kahn Jean Vicat Yvonne Soldo Alessandro Arcovito Stefano Della Longa Beatrice Vallone Agostina Congiu Castellano Jean Louis Hazemann 1999-11-01 https://www.openaccessrepository.it/record/102045 https://doi.org/10.1107/s0909049599010845 und unknown url:https://www.openaccessrepository.it/communities/itmirror https://www.openaccessrepository.it/record/102045 doi:10.1107/s0909049599010845 info:eu-repo/semantics/openAccess Instrumentation Nuclear and High Energy Physics Radiation info:eu-repo/semantics/article publication-article 1999 ftopenaccessrep https://doi.org/10.1107/s0909049599010845 2023-09-26T22:18:35Z Visible light can break the Fe—CO bond in Fe(II) carbonmonoxy-myoglobin (MbCO) giving an unligated product (Mb*) that is almost stable at T < 30 K. Fe K-edge polarized X-ray absorption spectra (P-XAS) of the photoproduct (T = 20 K) of an oriented single crystal (0.2 × 0.2 × 0.3 mm) of sperm whale MbCO (space group P21) have been collected. By rotating the crystal the X-ray photon polarization vector has been oriented almost parallel (with an angle α = 23°) or perpendicular (α = 86°) to the heme normal of each myoglobin molecule. The crystal was continuously illuminated by a white-light source during the data collection. The polarized data give novel information on the Fe-heme electronic/structural rearrangement following photolysis. The XANES (X-ray absorption near-edge structure) spectrum polarized in the direction close to the Fe—CO bond changes dramatically after photolysis, exhibiting a shift of ∼2 eV, due to electronic relaxation of empty states of pz symmetry, while more subtle changes are observed in the spectrum polarized along the heme plane, sensitive to the heme-plane geometry. Changes in the pre-edge region can be interpreted to provide insight into the electronic structure of the highest occupied and lowest unoccupied molecular orbitals (HOMO–LUMO) in the MbCO → Mb* photochemical reaction at low temperature. Article in Journal/Newspaper Sperm whale Istituto Nazionale di Fisica Nucleare (INFN): Open Access Repository Journal of Synchrotron Radiation 6 6 1138 1147 |
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Istituto Nazionale di Fisica Nucleare (INFN): Open Access Repository |
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unknown |
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Instrumentation Nuclear and High Energy Physics Radiation |
spellingShingle |
Instrumentation Nuclear and High Energy Physics Radiation Richard Kahn Jean Vicat Yvonne Soldo Alessandro Arcovito Stefano Della Longa Beatrice Vallone Agostina Congiu Castellano Jean Louis Hazemann Polarized X-ray absorption spectroscopy of the low-temperature photoproduct of carbonmonoxy-myoglobin |
topic_facet |
Instrumentation Nuclear and High Energy Physics Radiation |
description |
Visible light can break the Fe—CO bond in Fe(II) carbonmonoxy-myoglobin (MbCO) giving an unligated product (Mb*) that is almost stable at T < 30 K. Fe K-edge polarized X-ray absorption spectra (P-XAS) of the photoproduct (T = 20 K) of an oriented single crystal (0.2 × 0.2 × 0.3 mm) of sperm whale MbCO (space group P21) have been collected. By rotating the crystal the X-ray photon polarization vector has been oriented almost parallel (with an angle α = 23°) or perpendicular (α = 86°) to the heme normal of each myoglobin molecule. The crystal was continuously illuminated by a white-light source during the data collection. The polarized data give novel information on the Fe-heme electronic/structural rearrangement following photolysis. The XANES (X-ray absorption near-edge structure) spectrum polarized in the direction close to the Fe—CO bond changes dramatically after photolysis, exhibiting a shift of ∼2 eV, due to electronic relaxation of empty states of pz symmetry, while more subtle changes are observed in the spectrum polarized along the heme plane, sensitive to the heme-plane geometry. Changes in the pre-edge region can be interpreted to provide insight into the electronic structure of the highest occupied and lowest unoccupied molecular orbitals (HOMO–LUMO) in the MbCO → Mb* photochemical reaction at low temperature. |
format |
Article in Journal/Newspaper |
author |
Richard Kahn Jean Vicat Yvonne Soldo Alessandro Arcovito Stefano Della Longa Beatrice Vallone Agostina Congiu Castellano Jean Louis Hazemann |
author_facet |
Richard Kahn Jean Vicat Yvonne Soldo Alessandro Arcovito Stefano Della Longa Beatrice Vallone Agostina Congiu Castellano Jean Louis Hazemann |
author_sort |
Richard Kahn |
title |
Polarized X-ray absorption spectroscopy of the low-temperature photoproduct of carbonmonoxy-myoglobin |
title_short |
Polarized X-ray absorption spectroscopy of the low-temperature photoproduct of carbonmonoxy-myoglobin |
title_full |
Polarized X-ray absorption spectroscopy of the low-temperature photoproduct of carbonmonoxy-myoglobin |
title_fullStr |
Polarized X-ray absorption spectroscopy of the low-temperature photoproduct of carbonmonoxy-myoglobin |
title_full_unstemmed |
Polarized X-ray absorption spectroscopy of the low-temperature photoproduct of carbonmonoxy-myoglobin |
title_sort |
polarized x-ray absorption spectroscopy of the low-temperature photoproduct of carbonmonoxy-myoglobin |
publishDate |
1999 |
url |
https://www.openaccessrepository.it/record/102045 https://doi.org/10.1107/s0909049599010845 |
genre |
Sperm whale |
genre_facet |
Sperm whale |
op_relation |
url:https://www.openaccessrepository.it/communities/itmirror https://www.openaccessrepository.it/record/102045 doi:10.1107/s0909049599010845 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1107/s0909049599010845 |
container_title |
Journal of Synchrotron Radiation |
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6 |
container_issue |
6 |
container_start_page |
1138 |
op_container_end_page |
1147 |
_version_ |
1780741541464113152 |