1CWU: BRASSICA NAPUS ENOYL ACP REDUCTASE A138G MUTANT COMPLEXED WITH NAD+ AND THIENODIAZABORINE

Citation:
Abstract
Enoyl acyl carrier protein reductase (ENR) is involved in fatty acid biosynthesis. In Escherichia coli this enzyme is the target for the experimental family of antibacterial agents, the diazaborines, and for triclosan, a broad spectrum antimicrobial agent. Biochemical studies have suggested that the mechanism of diazaborine inhibition is dependent on NAD(+) and not NADH, and resistance of Brassica napus ENR to diazaborines is thought to be due to the replacement of a glycine in the active site of the E. coli enzyme by an alanine at position 138 in the plant homologue. We present here an x-ray analysis of crystals of B. napus ENR A138G grown in the presence of either NAD(+) or NADH and the structures of the corresponding ternary complexes with thienodiazaborine obtained either by soaking the drug into the crystals or by co-crystallization of the mutant with NAD(+) and diazaborine. Analysis of the ENR A138G complex with diazaborine and NAD(+) shows that the site of diazaborine binding is remarkably close to that reported for E. coli ENR. However, the structure of the ternary ENR A138G-NAD(+)-diazaborine complex obtained using co-crystallization reveals a previously unobserved conformational change affecting 11 residues that flank the active site and move closer to the nicotinamide moiety making extensive van der Waals contacts with diazaborine. Considerations of the mode of substrate binding suggest that this conformational change may reflect a structure of ENR that is important in catalysis.
PDB ID: 1CWUDownload
MMDB ID: 11228
PDB Deposition Date: 1999/8/26
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2.5  Å
Source Organism:
Similar Structures:
Biological Unit for 1CWU: tetrameric; determined by author and by software (PISA,PQS)
Molecular Components in 1CWU
Label Count Molecule
Proteins (4 molecules)
4
Enoyl ACP Reductase
Molecule annotation
Chemicals (8 molecules)
1
4
2
4
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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