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Proton Transfer Pathways in Nitrogenase with and without Dissociated S2B

Jiang, Hao LU orcid ; Svensson, Oskar K. G. LU ; Cao, Lili LU and Ryde, Ulf LU orcid (2022) In Angewandte Chemie (International edition) 61(39).
Abstract
Nitrogenase is the only enzyme that can convert N2 to NH3.
Crystallographic structures have indicated that one of the sulfide
ligands of the active-site FeMo cluster, S2B, can be replaced by an
inhibitor, like CO and OH−, and it has been suggested that it
may be displaced also during the normal reaction. We have investigated
possible proton transfer pathways within the FeMo cluster during the
conversion of N2H2 to two molecules of NH3,
assuming that the protons enter the cluster at the S3B, S4B or S5A
sulfide ions and are then transferred to the substrate. We use combined
quantum mechanical and molecular mechanical (QM/MM)... (More)
Nitrogenase is the only enzyme that can convert N2 to NH3.
Crystallographic structures have indicated that one of the sulfide
ligands of the active-site FeMo cluster, S2B, can be replaced by an
inhibitor, like CO and OH−, and it has been suggested that it
may be displaced also during the normal reaction. We have investigated
possible proton transfer pathways within the FeMo cluster during the
conversion of N2H2 to two molecules of NH3,
assuming that the protons enter the cluster at the S3B, S4B or S5A
sulfide ions and are then transferred to the substrate. We use combined
quantum mechanical and molecular mechanical (QM/MM) calculations with
the TPSS and B3LYP functionals. The calculations indicate that the
barriers for these reactions are reasonable if the S2B ligand remains
bound to the cluster, but they become prohibitively high if S2B has
dissociated. This suggests that it is unlikely that S2B reversibly
dissociates during the normal reaction cycle. (Less)
Please use this url to cite or link to this publication:
author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
nitrogenase, proton transfer, S2B dissociation, QM/MM, reaction mechanisms
in
Angewandte Chemie (International edition)
volume
61
issue
39
article number
e202208544
pages
9 pages
publisher
John Wiley & Sons Inc.
external identifiers
  • scopus:85136515421
  • pmid:35920055
ISSN
1521-3773
DOI
10.1002/anie.202208544
language
English
LU publication?
yes
id
f6dd80e5-04e6-4f7a-a955-65cc79aa53be
date added to LUP
2022-11-24 12:55:19
date last changed
2023-04-06 00:52:50
@article{f6dd80e5-04e6-4f7a-a955-65cc79aa53be,
  abstract     = {{Nitrogenase is the only enzyme that can convert N<sub>2</sub> to NH<sub>3</sub>.<br>
 Crystallographic structures have indicated that one of the sulfide <br>
ligands of the active-site FeMo cluster, S2B, can be replaced by an <br>
inhibitor, like CO and OH<sup>−</sup>, and it has been suggested that it<br>
 may be displaced also during the normal reaction. We have investigated <br>
possible proton transfer pathways within the FeMo cluster during the <br>
conversion of N<sub>2</sub>H<sub>2</sub> to two molecules of NH<sub>3</sub>,<br>
 assuming that the protons enter the cluster at the S3B, S4B or S5A <br>
sulfide ions and are then transferred to the substrate. We use combined <br>
quantum mechanical and molecular mechanical (QM/MM) calculations with <br>
the TPSS and B3LYP functionals. The calculations indicate that the <br>
barriers for these reactions are reasonable if the S2B ligand remains <br>
bound to the cluster, but they become prohibitively high if S2B has <br>
dissociated. This suggests that it is unlikely that S2B reversibly <br>
dissociates during the normal reaction cycle.}},
  author       = {{Jiang, Hao and Svensson, Oskar K. G. and Cao, Lili and Ryde, Ulf}},
  issn         = {{1521-3773}},
  keywords     = {{nitrogenase; proton transfer; S2B dissociation; QM/MM; reaction mechanisms}},
  language     = {{eng}},
  month        = {{08}},
  number       = {{39}},
  publisher    = {{John Wiley & Sons Inc.}},
  series       = {{Angewandte Chemie (International edition)}},
  title        = {{Proton Transfer Pathways in Nitrogenase with and without Dissociated S2B}},
  url          = {{http://dx.doi.org/10.1002/anie.202208544}},
  doi          = {{10.1002/anie.202208544}},
  volume       = {{61}},
  year         = {{2022}},
}