3TL1

Crystal structure of the Streptomyces coelicolor WhiE ORFVI polyketide aromatase/cyclase

Summary for 3TL1

• Entry DOI: 10.2210/pdb3tl1/pdb
• Descriptor: Polyketide cyclase, 6,7,9-trihydroxy-3-methyl-1H-benzo[g]isochromen-1-one, GLYCEROL, ... (4 entities in total)
• Functional Keywords: helix-grip fold, polyketide c9-c14 aromatase/cyclase, linear poly-beta-ketone intermediate, biosynthetic protein
• Biological source: Streptomyces coelicolor
• Total number of polymer chains: 2
• Total formula weight: 37225.41

Authors

Lee, M.-Y.,Ames, B.D.,Zhang, W.,Tang, Y.,Tsai, S.-C. (deposition date: 2011-08-29, release date: 2012-04-04, Last modification date: 2024-02-28)

Primary citation

Lee, M.Y.,Ames, B.D.,Tsai, S.C.
Insight into the Molecular Basis of Aromatic Polyketide Cyclization: Crystal Structure and in Vitro Characterization of WhiE-ORFVI.
Biochemistry, 51:3079-3091, 2012

PubMed Abstract: Aromatic polyketides are biologically active natural products. Many important pharmaceuticals are derived from aromatic polyketides. Especially important in aromatic polyketide biosynthesis is the regiospecific cyclization of a linear, preassembled polyketide chain catalyzed by aromatase/cyclase (ARO/CYC), which serves as a key control point in aromatic ring formation. How different ARO/CYCs promote different cyclization patterns is not well understood. The whiE locus of Streptomyces coelicolor A3(2) is responsible for the biosynthesis of an aromatic polyketide precursor to the gray spore pigment. The WhiE ARO/CYC catalyzes the regiospecific C9-C14 and C7-C16 cyclization and aromatization of a 24-carbon polyketide chain. WhiE ARO/CYC shares a high degree of similarity to another nonreducing PKS ARO/CYC, TcmN ARO/CYC. This paper presents the apo crystal structure of WhiE ARO/CYC, and cocrystal structures of WhiE and TcmN ARO/CYCs bound with polycyclic aromatic compounds that mimic the respective ARO/CYC products. Site-directed mutagenesis coupled with in vitro PKS reconstitution assays was used to characterize the interior pocket residues of WhiE ARO/CYC. The results confirmed that the interior pocket of ARO/CYCs is a critical determinant of polyketide cyclization specificity. A unified ARO/CYC-mediated cyclization mechanism is proposed on the basis of these structural and functional results.

PubMed: 22432862
DOI: 10.1021/bi201705q

Experimental method

X-RAY DIFFRACTION (1.8 Å)