Setting an Upper Limit on the Myoglobin Iron(IV)Hydroxide pK(a): Insight into Axial Ligand Tuning in Heme Protein Catalysis

[Image: see text] To provide insight into the iron(IV)hydroxide pK(a) of histidine ligated heme proteins, we have probed the active site of myoglobin compound II over the pH range of 3.9–9.5, using EXAFS, Mössbauer, and resonance Raman spectroscopies. We find no indication of ferryl protonation over...

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Autores principales: Yosca, Timothy H., Behan, Rachel K., Krest, Courtney M., Onderko, Elizabeth L., Langston, Matthew C., Green, Michael T.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2014
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4091272/
https://www.ncbi.nlm.nih.gov/pubmed/24875119
http://dx.doi.org/10.1021/ja503588n
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author Yosca, Timothy H.
Behan, Rachel K.
Krest, Courtney M.
Onderko, Elizabeth L.
Langston, Matthew C.
Green, Michael T.
author_facet Yosca, Timothy H.
Behan, Rachel K.
Krest, Courtney M.
Onderko, Elizabeth L.
Langston, Matthew C.
Green, Michael T.
author_sort Yosca, Timothy H.
collection PubMed
description [Image: see text] To provide insight into the iron(IV)hydroxide pK(a) of histidine ligated heme proteins, we have probed the active site of myoglobin compound II over the pH range of 3.9–9.5, using EXAFS, Mössbauer, and resonance Raman spectroscopies. We find no indication of ferryl protonation over this pH range, allowing us to set an upper limit of 2.7 on the iron(IV)hydroxide pK(a) in myoglobin. Together with the recent determination of an iron(IV)hydroxide pK(a) ∼ 12 in the thiolate-ligated heme enzyme cytochrome P450, this result provides insight into Nature’s ability to tune catalytic function through its choice of axial ligand.
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spelling pubmed-40912722015-05-29 Setting an Upper Limit on the Myoglobin Iron(IV)Hydroxide pK(a): Insight into Axial Ligand Tuning in Heme Protein Catalysis Yosca, Timothy H. Behan, Rachel K. Krest, Courtney M. Onderko, Elizabeth L. Langston, Matthew C. Green, Michael T. J Am Chem Soc [Image: see text] To provide insight into the iron(IV)hydroxide pK(a) of histidine ligated heme proteins, we have probed the active site of myoglobin compound II over the pH range of 3.9–9.5, using EXAFS, Mössbauer, and resonance Raman spectroscopies. We find no indication of ferryl protonation over this pH range, allowing us to set an upper limit of 2.7 on the iron(IV)hydroxide pK(a) in myoglobin. Together with the recent determination of an iron(IV)hydroxide pK(a) ∼ 12 in the thiolate-ligated heme enzyme cytochrome P450, this result provides insight into Nature’s ability to tune catalytic function through its choice of axial ligand. American Chemical Society 2014-05-29 2014-06-25 /pmc/articles/PMC4091272/ /pubmed/24875119 http://dx.doi.org/10.1021/ja503588n Text en Copyright © 2014 American Chemical Society Terms of Use (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html)
spellingShingle Yosca, Timothy H.
Behan, Rachel K.
Krest, Courtney M.
Onderko, Elizabeth L.
Langston, Matthew C.
Green, Michael T.
Setting an Upper Limit on the Myoglobin Iron(IV)Hydroxide pK(a): Insight into Axial Ligand Tuning in Heme Protein Catalysis
title Setting an Upper Limit on the Myoglobin Iron(IV)Hydroxide pK(a): Insight into Axial Ligand Tuning in Heme Protein Catalysis
title_full Setting an Upper Limit on the Myoglobin Iron(IV)Hydroxide pK(a): Insight into Axial Ligand Tuning in Heme Protein Catalysis
title_fullStr Setting an Upper Limit on the Myoglobin Iron(IV)Hydroxide pK(a): Insight into Axial Ligand Tuning in Heme Protein Catalysis
title_full_unstemmed Setting an Upper Limit on the Myoglobin Iron(IV)Hydroxide pK(a): Insight into Axial Ligand Tuning in Heme Protein Catalysis
title_short Setting an Upper Limit on the Myoglobin Iron(IV)Hydroxide pK(a): Insight into Axial Ligand Tuning in Heme Protein Catalysis
title_sort setting an upper limit on the myoglobin iron(iv)hydroxide pk(a): insight into axial ligand tuning in heme protein catalysis
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4091272/
https://www.ncbi.nlm.nih.gov/pubmed/24875119
http://dx.doi.org/10.1021/ja503588n
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