The HydG enzyme generates an Fe(CO)2(CN) synthon in assembly of the FeFe hydrogenase H-cluster.
Three iron-sulfur proteins--HydE, HydF, and HydG--play a key role in the synthesis of the [2Fe](H) component of the catalytic H-cluster of FeFe hydrogenase. The radical S-adenosyl-L-methionine enzyme HydG lyses free tyrosine to produce p-cresol and the CO and CN(-) ligands of the [2Fe](H) cluster. Here, we applied stopped-flow Fourier transform infrared and electron-nuclear double resonance spectroscopies to probe the formation of HydG-bound Fe-containing species bearing CO and CN(-) ligands with spectroscopic signatures that evolve on the 1- to 1000-second time scale. Through study of the (13)C, (15)N, and (57)Fe isotopologs of these intermediates and products, we identify the final HydG-bound species as an organometallic Fe(CO)2(CN) synthon that is ultimately transferred to apohydrogenase to form the [2Fe](H) component of the H-cluster.
Department of Chemistry, University of California, Davis, Davis, CA 95616, USA.
Jon M
JM
Kuchenreuther
William K
WK
Myers
Daniel L M
DL
Suess
Troy A
TA
Stich
Vladimir
V
Pelmenschikov
Stacey A
SA
Shiigi
Stephen P
SP
Cramer
James R
JR
Swartz
R David
RD
Britt
Simon J
SJ
George
D001426:Bacterial Proteins / Q000737:chemistry*; D002384:Catalysis; D020134:Catalytic Domain; D006864:Hydrogenase / Q000737:chemistry*; D054354:Iron Carbonyl Compounds / Q000378:metabolism*; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D020614:Shewanella putrefaciens / Q000201:enzymology; D017550:Spectroscopy, Fourier Transform Infrared
D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D054354:Iron Carbonyl Compounds; C118830:iron hydrogenase; D006864:Hydrogenase