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Publication Abstract from PubMed

Aromatic polyketides make up a large class of natural products with diverse bioactivity. During biosynthesis, linear poly-beta-ketone intermediates are regiospecifically cyclized, yielding molecules with defined cyclization patterns that are crucial for polyketide bioactivity. The aromatase/cyclases (ARO/CYCs) are responsible for regiospecific cyclization of bacterial polyketides. The two most common cyclization patterns are C7-C12 and C9-C14 cyclizations. We have previously characterized three monodomain ARO/CYCs: ZhuI, TcmN, and WhiE. The last remaining uncharacterized class of ARO/CYCs is the di-domain ARO/CYCs, which catalyze C7-C12 cyclization and/or aromatization. Di-domain ARO/CYCs can further be separated into two subclasses: "nonreducing" ARO/CYCs, which act on nonreduced poly-beta-ketones, and "reducing" ARO/CYCs, which act on cyclized C9 reduced poly-beta-ketones. For years, the functional role of each domain in cyclization and aromatization for di-domain ARO/CYCs has remained a mystery. Here we present what is to our knowledge the first structural and functional analysis, along with an in-depth comparison, of the nonreducing (StfQ) and reducing (BexL) di-domain ARO/CYCs. This work completes the structural and functional characterization of mono- and di-domain ARO/CYCs in bacterial type II polyketide synthases and lays the groundwork for engineered biosynthesis of new bioactive polyketides.

Structural and functional analysis of two di-domain aromatase/cyclases from type II polyketide synthases.,Caldara-Festin G, Jackson DR, Barajas JF, Valentic TR, Patel AB, Aguilar S, Nguyen M, Vo M, Khanna A, Sasaki E, Liu HW, Tsai SC Proc Natl Acad Sci U S A. 2015 Dec 2. pii: 201512976. PMID:26631750^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.