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Selenocyanate Derived Se-Incorporation into the Nitrogenase Fe Protein Cluster

Buscagan, Trixia M. and Kaiser, Jens T. and Rees, Douglas C. (2022) Selenocyanate Derived Se-Incorporation into the Nitrogenase Fe Protein Cluster. . (Unpublished)

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The nitrogenase Fe protein mediates ATP-dependent electron transfer to the nitrogenase MoFe protein during nitrogen fixation, in addition to catalyzing MoFe protein independent substrate (CO₂) reduction and facilitating MoFe protein metallocluster biosynthesis. The precise role(s) of the Fe protein Fe₄S₄ cluster in some of these processes remains ill-defined. Herein, we report crystallographic data demonstrating ATP-dependent chalcogenide exchange at the Fe₄S₄ cluster of the nitrogenase Fe protein when potassium selenocyanate is used as the selenium source. The observed chalcogenide exchange illustrates that this Fe₄S₄ cluster is capable of core substitution reactions under certain conditions, adding to the Fe protein’s repertoire of unique properties.

Item Type:Report or Paper (Discussion Paper)
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URLURL TypeDescription Paper
Buscagan, Trixia M.0000-0001-8242-9203
Kaiser, Jens T.0000-0002-5948-5212
Rees, Douglas C.0000-0003-4073-1185
Additional Information:The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY 4.0 International license. This version posted April 30, 2022. We dedicate this paper to Prof. James B. Howard and are grateful for our extensive exchanges on cluster atom exchanges—Jim really shaped the way we thought about the Fe protein cluster and our journeys with nitrogenase. We also thank Dr. Javier Fajardo Jr. for insightful discussions, Jeffrey Lai for growing Azotobacter vinelandii, and Dr. Paul Oyala for EPR training and support. The authors are grateful to the Gordon and Betty Moore Foundation, Don and Judy Voet, and the Beckman Institute at Caltech for their generous support of the Molecular Observatory at Caltech. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. The SSRL Structural Molecular Biology Program is supported by the DOE Office of Biological and Environmental Research, and by the National Institutes of Health, National Institute of General Medical Sciences (including P41GM103393). The Caltech EPR Facility is supported by NSF-1531940. This work was supported by the National Institute of Health (NIH Grant GM45162) and the Howard Hughes Medical Institute (HHMI). This article is subject to HHMI’s Open Access to Publications policy. HHMI lab heads have previously granted a nonexclusive CC BY 4.0 license to the public and a sublicensable license to HHMI in their research articles. Pursuant to those licenses, the author-accepted manuscript of this article can be made freely available under a CC BY 4.0 license immediately upon publication. The authors declare no competing financial interests.
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
Don and Judy VoetUNSPECIFIED
Caltech Beckman InstituteUNSPECIFIED
Department of Energy (DOE)DE-AC02-76SF00515
Howard Hughes Medical Institute (HHMI)UNSPECIFIED
Record Number:CaltechAUTHORS:20220511-226093100
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Official Citation:Selenocyanate Derived Se-Incorporation into the Nitrogenase Fe Protein Cluster. Trixia M. Buscagan, Jens T. Kaiser, Douglas C. Rees. bioRxiv 2022.04.29.490034; doi:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:114670
Deposited By: Tony Diaz
Deposited On:11 May 2022 21:30
Last Modified:11 May 2022 21:30

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