67024-17-3Relevant articles and documents
Thioesterase-Catalyzed Aminoacylation and Thiolation of Polyketides in Fungi
Tang, Man-Cheng,Fischer, Curt R.,Chari, Jason V.,Tan, Dan,Suresh, Sundari,Chu, Angela,Miranda, Molly,Smith, Justin,Zhang, Zhuan,Garg, Neil K.,Onge, Robert P. St.,Tang, Yi
, p. 8198 - 8206 (2020)
Fungal highly reducing polyketide synthases (HRPKSs) biosynthesize polyketides using a single set of domains iteratively. Product release is a critical step in HRPKS function to ensure timely termination and enzyme turnover. Nearly all of the HRPKSs characterized to date employ a separate thioesterase (TE) or acyltransferase enzyme for product release. In this study, we characterized two fungal HRPKSs that have fused C-terminal TE domains, a new domain architecture for fungal HRPKSs. We showed that both HRPKS-TEs synthesize aminoacylated polyketides in an ATPindependent fashion. The KU42 TE domain selects cysteine and homocysteine and catalyzes transthioesterification using the side-chain thiol group as the nucleophile. In contrast, the KU43 TE domain selects leucine methyl ester and performs a direct amidation of the polyketide, a reaction typically catalyzed by nonribosomal peptide synthetase (NRPS) domains. The characterization of these HRPKS-TE enzymes showcases the functional diversity of HRPKS enzymes and provides potential TE domains as biocatalytic tools to diversify HRPKS structures.
Seven-enzyme in vitro cascade to (3R)-3-hydroxybutyryl-CoA
Valencia, Luis E.,Zhang, Zhicheng,Cepeda, Alexis J.,Keatinge-Clay, Adrian T.
supporting information, p. 1375 - 1378 (2019/02/14)
Economical and environmentally-friendly routes to convert feedstock chemicals like acetate into valuable chiral products such as (R)-3-hydroxybutyrate are in demand. Here, seven enzymes (CoaA, CoaD, CoaE, ACS, BktB, PhaB, and GDH) are employed in a one-pot, in vitro, biocatalytic synthesis of (3R)-3-hydroxybutyryl-CoA, which was readily isolated. This platform generates not only chiral diketide building blocks but also desirable CoA derivatives.
In vitro kinetic study of the squalestatin tetraketide synthase dehydratase reveals the stereochemical course of a fungal highly reducing polyketide synthase
Liddle, Emma,Scott, Alan,Han, Li-Chen,Ivison, David,Simpson, Thomas J.,Willis, Christine L.,Cox, Russell J.
supporting information, p. 1727 - 1730 (2017/02/10)
Six potential diketide substrates for the squalestatin tetraketide synthase (SQTKS) dehydratase (DH) domain were synthesised as N-acetyl cysteamine thiolesters (SNAC) and tested in kinetic assays as substrates with an isolated DH domain. 3R-3-hydroxybutyryl SNAC 3R-16 was turned over by the enzyme, but its enantiomer was not. Of the four 2-methyl substrates only 2R,3R-2-methyl-3-hydroxybutyryl SNAC 2R,3R-8 was a substrate. Combined with stereochemical information from the isolated SQTKS enoyl reductase (ER) domain, our results provide a near complete stereochemical description of the first cycle of beta-modification reactions of a fungal highly reducing polyketide synthase (HR-PKS). The results emphasise the close relationship between fungal HR-PKS and vertebrate fatty acid synthases (vFAS).
