Context-dependent behavior of the enterocin iterative polyketide synthase; a new model for ketoreduction
Christian Hertweck1, Longkuan Xiang, John A Kalaitzis
1Hans-Knöll-Institute for Natural Products Research, Beutenbergstrasse 11a, 07745 Jena, Germany.
Abstract:
Heterologous expression and mutagenesis of the enterocin type II polyketide synthase (PKS) system suggest for the first time that the association of an extended set of proteins and substrates is needed for the effective production of the enterocin-wailupemycin polyketides. In the absence of its endogenous ketoreductase (KR) EncD in either the enterocin producer "Streptomyces maritimus" or the engineered host S. lividans K4-114, the enterocin minimal PKS is unable to produce benzoate-primed polyketides, even when complemented with the homologous actinorhodin KR ActIII or with EncD active site mutants. These data suggest that the enterocin PKS requires EncD to serve a catalytic and not just a structural role in the functional PKS enzyme complex. This strongly implies that EncD reduces the polyketide chain during elongation rather than after its complete assembly, as suggested for most type II PKSs.
More Related Videos
Related Concept Videos
α-Hydroxy Ketones via Reductive Coupling of Esters: Acyloin Condensation Overview
Thermal and Photochemical Electrocyclic Reactions: Overview
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Vicinal Diols via Reductive Coupling of Aldehydes or Ketones: Pinacol Coupling Overview
Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism


