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

ABSTRACT: Nitrogenase iron (Fe) proteins reduce CO₂ to CO and/or hydrocarbons under ambient conditions. Here, we report a 2.4-Å crystal structure of the Fe protein from Methanosarcina acetivorans (MaNifH), which is generated in the presence of a reductant, dithionite, and an alternative CO₂ source, bicarbonate. Structural analysis of this methanogen Fe protein species suggests that CO₂ is possibly captured in an unactivated, linear conformation near the [Fe₄S₄] cluster of MaNifH 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 CO₂ on MaNifH while suggesting a possible

SUBMITTER: Rettberg LA 

PROVIDER: S-EPMC6747716 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature