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Solvent Composition Drives the Rebinding Kinetics of Nitric Oxide to Microperoxidase

The rebinding kinetics of NO after photodissociation from microperoxidase (Mp-9) is studied in different solvent environments. In mixed glycerol/water (G/W) mixtures the dissociating ligand rebinds with a yield close to 1 due to the cavities formed by the solvent whereas in pure water the ligand can...

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Autores principales: Mondal, Padmabati, Meuwly, Markus
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5869715/
https://www.ncbi.nlm.nih.gov/pubmed/29588445
http://dx.doi.org/10.1038/s41598-018-22944-z
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author Mondal, Padmabati
Meuwly, Markus
author_facet Mondal, Padmabati
Meuwly, Markus
author_sort Mondal, Padmabati
collection PubMed
description The rebinding kinetics of NO after photodissociation from microperoxidase (Mp-9) is studied in different solvent environments. In mixed glycerol/water (G/W) mixtures the dissociating ligand rebinds with a yield close to 1 due to the cavities formed by the solvent whereas in pure water the ligand can diffuse into the solvent after photodissociation. In the G/W mixture, only geminate rebinding on the sub-picosecond and 5 ps time scales was found and the rebinding fraction is unity which compares well with available experiments. Contrary to that, simulations in pure water find two time scales – ~10 ps and ~200 ps - indicating that both, geminate rebinding and rebinding after diffusion of NO in the surrounding water contribute. The rebinding fraction is around 0.63 within 1 ns which is in stark contrast with experiment. Including ions (Na and Cl) at 0.15 M concentration in water leads to rebinding kinetics tending to that in the glycerol/water mixture and yields agreement with experiments. The effect of temperature is also probed and found to be non-negligible. The present simulations suggest that NO rebinding in Mp is primarily driven by thermal fluctuations which is consistent with recent resonance Raman spectroscopy experiments and simulations on MbNO.
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spelling pubmed-58697152018-04-02 Solvent Composition Drives the Rebinding Kinetics of Nitric Oxide to Microperoxidase Mondal, Padmabati Meuwly, Markus Sci Rep Article The rebinding kinetics of NO after photodissociation from microperoxidase (Mp-9) is studied in different solvent environments. In mixed glycerol/water (G/W) mixtures the dissociating ligand rebinds with a yield close to 1 due to the cavities formed by the solvent whereas in pure water the ligand can diffuse into the solvent after photodissociation. In the G/W mixture, only geminate rebinding on the sub-picosecond and 5 ps time scales was found and the rebinding fraction is unity which compares well with available experiments. Contrary to that, simulations in pure water find two time scales – ~10 ps and ~200 ps - indicating that both, geminate rebinding and rebinding after diffusion of NO in the surrounding water contribute. The rebinding fraction is around 0.63 within 1 ns which is in stark contrast with experiment. Including ions (Na and Cl) at 0.15 M concentration in water leads to rebinding kinetics tending to that in the glycerol/water mixture and yields agreement with experiments. The effect of temperature is also probed and found to be non-negligible. The present simulations suggest that NO rebinding in Mp is primarily driven by thermal fluctuations which is consistent with recent resonance Raman spectroscopy experiments and simulations on MbNO. Nature Publishing Group UK 2018-03-27 /pmc/articles/PMC5869715/ /pubmed/29588445 http://dx.doi.org/10.1038/s41598-018-22944-z Text en © The Author(s) 2018 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Mondal, Padmabati
Meuwly, Markus
Solvent Composition Drives the Rebinding Kinetics of Nitric Oxide to Microperoxidase
title Solvent Composition Drives the Rebinding Kinetics of Nitric Oxide to Microperoxidase
title_full Solvent Composition Drives the Rebinding Kinetics of Nitric Oxide to Microperoxidase
title_fullStr Solvent Composition Drives the Rebinding Kinetics of Nitric Oxide to Microperoxidase
title_full_unstemmed Solvent Composition Drives the Rebinding Kinetics of Nitric Oxide to Microperoxidase
title_short Solvent Composition Drives the Rebinding Kinetics of Nitric Oxide to Microperoxidase
title_sort solvent composition drives the rebinding kinetics of nitric oxide to microperoxidase
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5869715/
https://www.ncbi.nlm.nih.gov/pubmed/29588445
http://dx.doi.org/10.1038/s41598-018-22944-z
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