Computational study of the structure and electronic circular dichroism spectroscopy of blue copper proteins

The calculation of the electronic circular dichroism (CD) spectra of the oxidised form of the blue copper proteins plastocyanin and cucumber basic protein and the relationship between the observed spectral features and the structure of the active site of the protein is investigated. Excitation energ...

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Main Authors: Do, Hainam, Deeth, Robert J., Besley, Nicholas A.
Format: Article
Published: American Chemical Society 2013
Subjects:
Online Access:https://eprints.nottingham.ac.uk/29971/
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author Do, Hainam
Deeth, Robert J.
Besley, Nicholas A.
author_facet Do, Hainam
Deeth, Robert J.
Besley, Nicholas A.
author_sort Do, Hainam
building Nottingham Research Data Repository
collection Online Access
description The calculation of the electronic circular dichroism (CD) spectra of the oxidised form of the blue copper proteins plastocyanin and cucumber basic protein and the relationship between the observed spectral features and the structure of the active site of the protein is investigated. Excitation energies and transition strengths are computed using multi reference configuration interaction, and it is shown that computed spectra based on coordinates from the crystal structure or a single structure optimised in quantum mechanics/molecular mechanics (QM/MM) or ligand field molecular mechanics (LFMM) are qualitatively incorrect. In particular, the rotational strength of the ligand to metal charge transfer band is predicted to be too small or have the incorrect sign. By considering calculations on active site models with modified structures it is shown that the intensity of this band is sensitive to the non-planarity of the histidine and cysteine ligands coordinated to copper. Calculation of the ultraviolet absorption and CD spectra based upon averaging over many structures drawn from a LFMM molecular dynamics simulation are in good agreement with experiment, and superior to analogous calculations based upon structures from a classical molecular dynamics simulation. This provides evidence that the LFMM force field provides an accurate description of the molecular dynamics of these proteins.
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spelling nottingham-299712020-05-04T16:37:19Z https://eprints.nottingham.ac.uk/29971/ Computational study of the structure and electronic circular dichroism spectroscopy of blue copper proteins Do, Hainam Deeth, Robert J. Besley, Nicholas A. The calculation of the electronic circular dichroism (CD) spectra of the oxidised form of the blue copper proteins plastocyanin and cucumber basic protein and the relationship between the observed spectral features and the structure of the active site of the protein is investigated. Excitation energies and transition strengths are computed using multi reference configuration interaction, and it is shown that computed spectra based on coordinates from the crystal structure or a single structure optimised in quantum mechanics/molecular mechanics (QM/MM) or ligand field molecular mechanics (LFMM) are qualitatively incorrect. In particular, the rotational strength of the ligand to metal charge transfer band is predicted to be too small or have the incorrect sign. By considering calculations on active site models with modified structures it is shown that the intensity of this band is sensitive to the non-planarity of the histidine and cysteine ligands coordinated to copper. Calculation of the ultraviolet absorption and CD spectra based upon averaging over many structures drawn from a LFMM molecular dynamics simulation are in good agreement with experiment, and superior to analogous calculations based upon structures from a classical molecular dynamics simulation. This provides evidence that the LFMM force field provides an accurate description of the molecular dynamics of these proteins. American Chemical Society 2013-06-17 Article PeerReviewed Do, Hainam, Deeth, Robert J. and Besley, Nicholas A. (2013) Computational study of the structure and electronic circular dichroism spectroscopy of blue copper proteins. Journal of Physical Chemistry B, 117 (27). pp. 8105-8112. ISSN 1520-52707 plastocyanin cucumber basic protein ligand-field molecular mechanics molecular dynamics http://pubs.acs.org/doi/abs/10.1021/jp404107j doi:10.1021/jp404107j doi:10.1021/jp404107j
spellingShingle plastocyanin
cucumber basic protein
ligand-field molecular mechanics
molecular dynamics
Do, Hainam
Deeth, Robert J.
Besley, Nicholas A.
Computational study of the structure and electronic circular dichroism spectroscopy of blue copper proteins
title Computational study of the structure and electronic circular dichroism spectroscopy of blue copper proteins
title_full Computational study of the structure and electronic circular dichroism spectroscopy of blue copper proteins
title_fullStr Computational study of the structure and electronic circular dichroism spectroscopy of blue copper proteins
title_full_unstemmed Computational study of the structure and electronic circular dichroism spectroscopy of blue copper proteins
title_short Computational study of the structure and electronic circular dichroism spectroscopy of blue copper proteins
title_sort computational study of the structure and electronic circular dichroism spectroscopy of blue copper proteins
topic plastocyanin
cucumber basic protein
ligand-field molecular mechanics
molecular dynamics
url https://eprints.nottingham.ac.uk/29971/
https://eprints.nottingham.ac.uk/29971/
https://eprints.nottingham.ac.uk/29971/