High-Resolution Structure of the Nitrile Reductase QueF Combined with Molecular Simulations Provide Insight into Enzyme Mechanism |
| |
Authors: | Youngchang Kim Shiu Moy Mark A Cunningham Andrzej Joachimiak |
| |
Institution: | 1 The Midwest Center for Structural Genomics and Structural Biology Center, Biosciences, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA2 Physics and Geology, The University of Texas-Pan American, 1201 West University Drive, Edinburg, TX 78539, USA |
| |
Abstract: | Here, we report the 1.53-Å crystal structure of the enzyme 7-cyano-7-deazaguanine reductase (QueF) from Vibrio cholerae, which is responsible for the complete reduction of a nitrile (C N) bond to a primary amine (H2C-NH2). At present, this is the only example of a biological pathway that includes reduction of a nitrile bond, establishing QueF as particularly noteworthy. The structure of the QueF monomer resembles two connected ferrodoxin-like domains that assemble into dimers. Ligands identified in the crystal structure suggest the likely binding conformation of the native substrates NADPH and 7-cyano-7-deazaguanine. We also report on a series of numerical simulations that have shed light on the mechanism by which this enzyme affects the transfer of four protons (and electrons) to the 7-cyano-7-deazaguanine substrate. In particular, the simulations suggest that the initial step of the catalytic process is the formation of a covalent adduct with the residue Cys194, in agreement with previous studies. The crystal structure also suggests that two conserved residues (His233 and Asp102) play an important role in the delivery of a fourth proton to the substrate. |
| |
Keywords: | QueF 7-cyano-7-deazaguanine reductase preQ0 7-cyano-7-deazaguanine preQ1 7-aminomethyl-7-deazaguanine T-fold tunneling fold QM/MM hybrid quantum/classical PDB Protein Data Bank NEB nudged elastic band SAD single-wavelength anomalous dispersion |
本文献已被 ScienceDirect 等数据库收录! |
|