Skip to main content
eScholarship
Open Access Publications from the University of California

Tracing the 'ninth sulfur' of the nitrogenase cofactor via a semi-synthetic approach.

  • Author(s): Tanifuji, Kazuki
  • Lee, Chi Chung
  • Sickerman, Nathaniel S
  • Tatsumi, Kazuyuki
  • Ohki, Yasuhiro
  • Hu, Yilin
  • Ribbe, Markus W
  • et al.
Abstract

The M-cluster is the [(homocitrate)MoFe7S9C] active site of nitrogenase that is derived from an 8Fe core assembled viacoupling and rearrangement of two [Fe4S4] clusters concomitant with the insertion of an interstitial carbon and a 'ninth sulfur'. Combining synthetic [Fe4S4] clusters with an assembly protein template, here we show that sulfite can give rise to the ninth sulfur that is incorporated in the catalytically important belt region of the cofactor after the radical S-adenosyl-L-methionine-dependent carbide insertion and the concurrent 8Fe-core rearrangement have already taken place. Based on the differential reactivity of the formed cluster species, we also propose a new [Fe8S8C] cluster intermediate, the L*-cluster, which is similar to the [Fe8S9C] L-cluster, but lacks the ninth sulfur from sulfite. This work provides a semi-synthetic tool for protein reconstitution that could be widely applicable for the functional analysis of other FeS systems.

Many UC-authored scholarly publications are freely available on this site because of the UC Academic Senate's Open Access Policy. Let us know how this access is important for you.

Main Content
Current View