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Spectroscopic Characterization of an Eight-Iron Nitrogenase Cofactor Precursor that Lacks the "9 th Sulfur".

Authors :
Jasniewski AJ
Wilcoxen J
Tanifuji K
Hedman B
Hodgson KO
Britt RD
Hu Y
Ribbe MW
Source :
Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2019 Oct 07; Vol. 58 (41), pp. 14703-14707. Date of Electronic Publication: 2019 Sep 05.
Publication Year :
2019

Abstract

Nitrogenases catalyze the reduction of N <subscript>2</subscript> to NH <subscript>4</subscript> <superscript>+</superscript> at its cofactor site. Designated the M-cluster, this [MoFe <subscript>7</subscript> S <subscript>9</subscript> C(R-homocitrate)] cofactor is synthesized via the transformation of a [Fe <subscript>4</subscript> S <subscript>4</subscript> ] cluster pair into an [Fe <subscript>8</subscript> S <subscript>9</subscript> C] precursor (designated the L-cluster) prior to insertion of Mo and homocitrate. We report the characterization of an eight-iron cofactor precursor (designated the L*-cluster), which is proposed to have the composition [Fe <subscript>8</subscript> S <subscript>8</subscript> C] and lack the "9 <superscript>th</superscript> sulfur" in the belt region of the L-cluster. Our X-ray absorption and electron spin echo envelope modulation (ESEEM) analyses strongly suggest that the L*-cluster represents a structural homologue to the l-cluster except for the missing belt sulfur. The absence of a belt sulfur from the L*-cluster may prove beneficial for labeling the catalytically important belt region, which could in turn facilitate investigations into the reaction mechanism of nitrogenases.<br /> (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Details

Language :
English
ISSN :
1521-3773
Volume :
58
Issue :
41
Database :
MEDLINE
Journal :
Angewandte Chemie (International ed. in English)
Publication Type :
Academic Journal
Accession number :
31411369
Full Text :
https://doi.org/10.1002/anie.201907593