Structure of PqsD, a Pseudomonas Quinolone Signal Biosynthetic Enzyme, in Complex with Anthranilate
Here we present a structural and biophysical characterization of PqsD that includes several crystal structures of the enzyme, including that of the PqsD-anthranilate covalent intermediate and the inactive Cys112Ala active site mutant in complex with anthranilate. The structure reveals that PqsD is structurally similar to the FabH and chalcone synthase families of fatty acid and polyketide synthases. The crystallographic asymmetric unit contains a PqsD dimer. The PqsD monomer is composed of two nearly identical 170-residue ????? domains. The structures show anthranilate-liganded Cys112 is positioned deep in the protein interior at the bottom of an 15 A long channel while a second anthraniloyl-CoA molecule is waiting in the cleft leading to the protein surface. Cys112, His257, and Asn287 form the FabH-like catalytic triad of PqsD. The C112A mutant is inactive, although it still reversibly binds anthraniloyl-CoA. The covalent complex between anthranilate and Cys112 clearly illuminates the orientation of key elements of the PqsD catalytic machinery and represents a snapshot of a key point in the catalytic cycle.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 980556
- Report Number(s):
- BNL-93474-2010-JA; TRN: US201015%%1941
- Journal Information:
- Biochemistry, Vol. 48, Issue 36
- Country of Publication:
- United States
- Language:
- English
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