7VWK

The product template domain of AviM

Summary for 7VWK

• Entry DOI: 10.2210/pdb7vwk/pdb
• Descriptor: Polyketide synthase (2 entities in total)
• Functional Keywords: iterative polyketide synthase, product template domain, c2-c7 cyclization, antibiotic
• Biological source: Streptomyces viridochromogenes Tue57
• Total number of polymer chains: 2
• Total formula weight: 54491.33

Authors

Feng, Y.,Yang, X.,Zheng, J. (deposition date: 2021-11-10, release date: 2022-06-08, Last modification date: 2024-05-29)

Primary citation

Feng, Y.,Yang, X.,Ji, H.,Deng, Z.,Lin, S.,Zheng, J.
The Streptomyces viridochromogenes product template domain represents an evolutionary intermediate between dehydratase and aldol cyclase of type I polyketide synthases.
Commun Biol, 5:508-508, 2022

PubMed Abstract: The product template (PT) domains act as an aldol cyclase to control the regiospecific aldol cyclization of the extremely reactive poly-β-ketone intermediate assembled by an iterative type I polyketide synthases (PKSs). Up to now, only the structure of fungal PksA PT that mediates the first-ring cyclization via C4-C9 aldol cyclization is available. We describe here the structural and computational characterization of a bacteria PT domain that controls C2-C7 cyclization in orsellinic acid (OSA) synthesis. Mutating the catalytic H949 of the PT abolishes production of OSA and results in a tetraacetic acid lactone (TTL) generated by spontaneous O-C cyclization of the acyl carrier protein (ACP)-bound tetraketide intermediate. Crystal structure of the bacterial PT domain closely resembles dehydrase (DH) domains of modular type I PKSs in the overall fold, dimerization interface and His-Asp catalytic dyad organization, but is significantly different from PTs of fungal iterative type I PKSs. QM/MM calculation suggests that the catalytic H949 abstracts a proton from C2 and transfers it to C7 carbonyl to mediate the cyclization reaction. According to structural similarity to DHs and functional similarity to fungal PTs, we propose that the bacterial PT represents an evolutionary intermediate between the two tailoring domains of type I PKSs.

PubMed: 35618872
DOI: 10.1038/s42003-022-03477-8

Experimental method

X-RAY DIFFRACTION (2 Å)