4J1Q

Crystal structure of a ketoreductase domain from the bacillaene assembly line

Summary for 4J1Q

• Entry DOI: 10.2210/pdb4j1q/pdb
• Related: 4J1S
• Descriptor: Polyketide synthase PksJ, NADPH DIHYDRO-NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE (2 entities in total)
• Functional Keywords: rossmann fold, ketoreductase, oxidoreductase
• Biological source: Bacillus subtilis subsp. subtilis
• Cellular location: Cytoplasm: P40806
• Total number of polymer chains: 1
• Total formula weight: 53260.99

Authors

Zheng, J.,Keatinge-Clay, A.T. (deposition date: 2013-02-01, release date: 2014-03-19, Last modification date: 2024-02-28)

Primary citation

Piasecki, S.K.,Zheng, J.,Axelrod, A.J.,E Detelich, M.,Keatinge-Clay, A.T.
Structural and functional studies of a trans-acyltransferase polyketide assembly line enzyme that catalyzes stereoselective alpha- and beta-ketoreduction.
Proteins, 82:2067-2077, 2014

PubMed Abstract: While the cis-acyltransferase modular polyketide synthase assembly lines have largely been structurally dissected, enzymes from within the recently discovered trans-acyltransferase polyketide synthase assembly lines are just starting to be observed crystallographically. Here we examine the ketoreductase (KR) from the first polyketide synthase module of the bacillaene nonribosomal peptide synthetase/polyketide synthase at 2.35-Å resolution. This KR naturally reduces both α- and β-keto groups and is the only KR known to do so during the biosynthesis of a polyketide. The isolated KR not only reduced an N-acetylcysteamine-bound β-keto substrate to a D-β-hydroxy product, but also an N-acetylcysteamine-bound α-keto substrate to an L-α-hydroxy product. That the substrates must enter the active site from opposite directions to generate these stereochemistries suggests that the acyl-phosphopantetheine moiety is capable of accessing very different conformations despite being anchored to a serine residue of a docked acyl carrier protein. The features enabling stereocontrolled α-ketoreduction may not be extensive since a KR that naturally reduces a β-keto group within a cis-acyltransferase polyketide synthase was identified that performs a completely stereoselective reduction of the same α-keto substrate to generate the D-α-hydroxy product. A sequence analysis of trans-acyltransferase KRs reveals that a single residue, rather than a three-residue motif found in cis-acyltransferase KRs, is predictive of the orientation of the resulting β-hydroxyl group.

PubMed: 24634061
DOI: 10.1002/prot.24561

Experimental method

X-RAY DIFFRACTION (2.35 Å)