ja5b12512_si_001.pdf (1.95 MB)
The Radical SAM Enzyme HydG Requires Cysteine and a Dangler Iron for Generating an Organometallic Precursor to the [FeFe]-Hydrogenase H‑Cluster
journal contribution
posted on 2016-02-03, 00:00 authored by Daniel
L. M. Suess, Cindy C. Pham, Ingmar Bürstel, James R. Swartz, Stephen P. Cramer, R. David BrittThree maturase enzymesHydE,
HydF, and HydGsynthesize
and insert the organometallic component of the [FeFe]-hydrogenase
active site (the H-cluster). HydG generates the first organometallic
intermediates in this process, ultimately producing an [Fe(CO)2(CN)] complex. A limitation in understanding the mechanism
by which this complex forms has been uncertainty regarding the precise
metallocluster composition of HydG that comprises active enzyme. We
herein show that the HydG auxiliary cluster must bind both l-cysteine and a dangler Fe in order to generate the [Fe(CO)2(CN)] product. These findings support a mechanistic framework in
which a [(Cys)Fe(CO)2(CN)]− species is
a key intermediate in H-cluster maturation.