6HXA image
Entry Detail
PDB ID:
6HXA
Keywords:
Title:
AntI from P. luminescens catalyses terminal polyketide shortening in the biosynthesis of anthraquinones
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2018-10-16
Release Date:
2019-08-07
Method Details:
Experimental Method:
Resolution:
1.85 Å
R-Value Free:
0.20
R-Value Work:
0.16
R-Value Observed:
0.16
Space Group:
C 2 2 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:AntI
Chain IDs:A
Chain Length:399
Number of Molecules:1
Biological Source:Photorhabdus luminescens
Primary Citation
Molecular mechanism of polyketide shortening in anthraquinone biosynthesis ofPhotorhabdus luminescens.
Chem Sci 10 6341 6349 (2019)
PMID: 31341589 DOI: 10.1039/c9sc00749k

Abstact

Anthraquinones, a widely distributed class of aromatic natural products, are produced by a type II polyketide synthase system in the Gram-negative bacterium Photorhabdus luminescens. Heterologous expression of the antABCDEFGHI anthraquinone biosynthetic gene cluster in Escherichia coli identified AntI as an unusual lyase, catalysing terminal polyketide shortening prior to formation of the third aromatic ring. Functional in vitro and in vivo analysis of AntI using X-ray crystallography, structure-based mutagenesis, and molecular simulations revealed that AntI converts a defined octaketide to the tricyclic anthraquinone ring via retro-Claisen and Dieckmann reactions. Thus, AntI catalyses a so far unobserved multistep reaction in this PKS system.

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