6NZJ

Structural Analysis of a Nitrogenase Iron Protein from Methanosarcina acetivorans: Implications for CO2 Capture by a Surface-Exposed [Fe4S4] Cluster

Summary for 6NZJ

• Entry DOI: 10.2210/pdb6nzj/pdb
• Descriptor: Nitrogenase iron protein, IRON/SULFUR CLUSTER, SULFATE ION, ... (4 entities in total)
• Functional Keywords: nitrogenase, iron protein, fes cluster, methanosarcina acetivorans, electron transport, oxidoreductase
• Biological source: Methanosarcina acetivorans (strain ATCC 35395 / DSM 2834 / JCM 12185 / C2A)
• Total number of polymer chains: 2
• Total formula weight: 59187.04

Authors

Rettberg, L.A.,Kang, W.,Stiebritz, M.T.,Hiller, C.J.,Lee, C.C.,Liedtke, J.,Ribbe, M.W.,Hu, Y. (deposition date: 2019-02-13, release date: 2019-06-26, Last modification date: 2023-10-11)

Primary citation

Rettberg, L.A.,Kang, W.,Stiebritz, M.T.,Hiller, C.J.,Lee, C.C.,Liedtke, J.,Ribbe, M.W.,Hu, Y.
Structural Analysis of a Nitrogenase Iron Protein from Methanosarcina acetivorans: Implications for CO 2 Capture by a Surface-Exposed [Fe 4 S 4 ] Cluster.
Mbio, 10:-, 2019

PubMed Abstract: Nitrogenase iron (Fe) proteins reduce CO to CO and/or hydrocarbons under ambient conditions. Here, we report a 2.4-Å crystal structure of the Fe protein from (NifH), which is generated in the presence of a reductant, dithionite, and an alternative CO source, bicarbonate. Structural analysis of this methanogen Fe protein species suggests that CO is possibly captured in an unactivated, linear conformation near the [FeS] cluster of NifH by a conserved arginine (Arg) pair in a concerted and, possibly, asymmetric manner. Density functional theory calculations and mutational analyses provide further support for the capture of CO on NifH while suggesting a possible role of Arg in the initial coordination of CO via hydrogen bonding and electrostatic interactions. These results provide a useful framework for further mechanistic investigations of CO activation by a surface-exposed [FeS] cluster, which may facilitate future development of FeS catalysts for ambient conversion of CO into valuable chemical commodities. This work reports the crystal structure of a previously uncharacterized Fe protein from a methanogenic organism, which provides important insights into the structural properties of the less-characterized, yet highly interesting archaeal nitrogenase enzymes. Moreover, the structure-derived implications for CO capture by a surface-exposed [FeS] cluster point to the possibility of developing novel strategies for CO sequestration while providing the initial insights into the unique mechanism of FeS-based CO activation.

PubMed: 31289188
DOI: 10.1128/mBio.01497-19

Experimental method

X-RAY DIFFRACTION (2.4 Å)