3BP1: Crystal Structure Of Putative 7-Cyano-7-Deazaguanine Reductase Quef From Vibrio Cholerae O1 Biovar Eltor

Here, we report the 1.53-A crystal structure of the enzyme 7-cyano-7-deazaguanine reductase (QueF) from Vibrio cholerae, which is responsible for the complete reduction of a nitrile (CN) bond to a primary amine (H(2)C-NH(2)). 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.
PDB ID: 3BP1Download
MMDB ID: 61729
PDB Deposition Date: 2007/12/18
Updated in MMDB: 2012/10
Experimental Method:
x-ray diffraction
Resolution: 1.53  Å
Source Organism:
Similar Structures:
Biological Unit for 3BP1: tetrameric; determined by author
Molecular Components in 3BP1
Label Count Molecule
Proteins (4 molecules)
Nadph-dependent 7-cyano-7-deazaguanine Reductase
Molecule annotation
Chemicals (14 molecules)
* Click molecule labels to explore molecular sequence information.

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