Enzymatic N2 activation: general discussion

Fatima Abi Ghaida, Katharina Brinkert, Ping Chen, Serena DeBeer, Brian M Hoffman, Patrick L. Holland, Shoba Laxmi, Doug MacFarlane, Jonas C. Peters, John W. Peters, Christopher J. Pickett, Lance C. Seefeldt, Sergii I. Shylin, Ifan E.L. Stephens, Kylie A. Vincent, Qianru Wang, Olivia Westhead

Research output: Contribution to journalComment / DebateOtherpeer-review

Abstract

Kylie A. Vincent opened a discussion of the paper by Lance C. Seefeldt: Couldyou comment on how the a-valine 70 to isoleucine mutation affects the binding ofother substrates or inhibitors beyond dinitrogen?

Lance C. Seefeldt replied: This is detailed in ref. 1.1 R. Y. Igarashi, M. Laryukhin, P. C. Dos Santos, H.-I. Lee, D. R. Dean, L. C. Seefeldt and B. M. Hoffman, Trapping H− Bound to the Nitrogenase Fe Mo-Cofactor Active Site during H 2 evolution: Characterization by ENDOR Spectroscopy, J. Am. Chem. Soc., 2005, 127,6231–6241.

Serena DeBeer remarked: In your talk (https://doi.org/10.1039/d2fd00153e) you suggest that you cannot do reductive elimination without N2 binding. But in principle, one also releases H2 via a similar route from E 2 without N 2 binding. Could you comment on the differences in H 2 release from E2 vs. E 4 ?

Lance C. Seefeldt answered: Hydride protonolysis to make H 2 occurs at both E 2and E 4 . At E 4 , this reaction is in competition with the reductive elimination of twohydrides to form H 2. This latter reaction requires the binding of N 2 .Ping Chen queried: Do protons only come from sulfur or from the surround-ings, e.g. from solution?

Lance C. Seefeldt answered: Protons ultimately come from the solvent. It is not fully known how the protons are held at the active site for delivery for substrate reduction, but it has been proposed that one or more of the metal-cofactor-bridging sulfdes could be a binding site for protons.
Original languageEnglish
Pages (from-to)287-295
Number of pages9
JournalFaraday Discussions
Volume243
DOIs
Publication statusPublished - 26 Jun 2023

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