Enzymatic formation of an unnatural methylated triketide by plant type III polyketide synthases
摘要:
Octaketide synthase, a novel plant-specific type III polyketide synthase from Aloe arborescens, efficiently accepted (2RS)-methylmalonyl-CoA as a sole substrate to produce 6-ethyl-4-hydroxy-3,5-dimethyl-2-pyrone. On the other hand, a tetraketide-producing chalcone synthase from Scutellaria baicalensis and a diketide-producing benzalacetone synthase from Rheum palmatum also yielded the unnatural methylated C-9 triketide pyrone as a single product by sequential decarboxylative condensations of three molecules of (2RS)-methylmalonyl-CoA. (c) 2006 Elsevier Ltd. All rights reserved.
DOI:
10.1016/j.tetlet.2006.10.012
作为产物:
描述:
甲基丙二酸 、 coenzyme A 在
malonyl-CoA synthetase from Rhizobium trifolii 、 5’-三磷酸腺苷 、 magnesium chloride 作用下,
以
aq. phosphate buffer 为溶剂,
反应 3.0h,
生成 methylmalonyl CoA
Synthetic Chain Terminators Off-Load Intermediates from a Type I Polyketide Synthase
作者:Manuela Tosin、Lorena Betancor、Elaine Stephens、W. M. Ariel Li、Jonathan B. Spencer、Peter F. Leadlay
DOI:10.1002/cbic.200900772
日期:2010.3.1
To catch and off load: Intermediate species in typeI modular polyketide biosynthesis were captured in vitro by small molecules that efficiently compete with the natural methylmalonyl extender units recruited for polyketide formation. The intermediates, which were directly off‐loaded from a whole polyketidesynthase in action and characterised by LC‐HR‐ESI‐MS, are the first of their kind and prove
[reaction: see text] In the chalconesynthase (CHS) enzyme reaction, both the starter molecule and the extension unit of the polyketide chain elongation reaction were simultaneously replaced with nonphysiological substrates. When incubated with benzoyl-CoA and methylmalonyl-CoA as substrates, recombinant CHS from Scutellaria baicalensis afforded an unnatural novel triketide, 4-hydroxy-3,5-dimethyl
Characterization of AntB, a Promiscuous Acyltransferase Involved in Antimycin Biosynthesis
作者:Moriah Sandy、Xuejun Zhu、Zhe Rui、Wenjun Zhang
DOI:10.1021/ol4014365
日期:2013.7.5
The in vivo and in vitro characterization of AntB, a dedicated acyltransferase encoded in the antimycin biosynthetic gene cluster, which catalyzes the C-8 acyloxy formation is reported. It is demonstrated that AntB has broad substrate specificity toward both the acyl substrate and the acyl carrier and produces more antimycin analogues with varying C-8 acyloxy moieties.
Synthesis and Biochemical Analysis of Complex Chain-Elongation Intermediates for Interrogation of Molecular Specificity in the Erythromycin and Pikromycin Polyketide Synthases
作者:Jonathan D. Mortison、Jeffrey D. Kittendorf、David H. Sherman
DOI:10.1021/ja9060596
日期:2009.11.4
The 6-deoxyerythronolide B synthase (DEBS) and pikromycin (Pik) polyketide synthase (PKS) are unique multifunctional enzyme systems that are responsible for the biosynthesis of the erythromycin and pikromycin 14-membered ring aglycones, respectively. Together, these natural product biosynthetic systems provide excellent platforms to examine the fundamental structural and catalytic elements that govern polyketide assembly, processing, and macrocyclization. In these studies, the native pentaketide intermediate for DEBS was synthesized and employed for in vitro chemoenzymatic synthesis of macrolactone products in engineered monomodules Ery5, Ery5-TE, and Ery6. A comparative analysis was performed with the corresponding Pik module 5 (PikAIII) and module 6 (PikAIV), dissecting key similarities and differences between these highly related PKSs. The data revealed that individual modules in the DEBS and Pik PKSs possess distinctive molecular selectivity profiles and suggest that substrate recognition has evolved unique characteristics in each system.
Poly Specific <i>trans</i>-Acyltransferase Machinery Revealed <i>via</i> Engineered Acyl-CoA Synthetases
作者:Irina Koryakina、John McArthur、Shan Randall、Matthew M. Draelos、Ewa M. Musiol、David C. Muddiman、Tilmann Weber、Gavin J. Williams
DOI:10.1021/cb3003489
日期:2013.1.18
Polyketidesynthases construct polyketides with diverse structures and biological activities via the condensation of extenderunits and acyl thioesters. Although a growing body of evidence suggests that polyketidesynthases might be tolerant to non-natural extenderunits, in vitro and in vivo studies aimed at probing and utilizing polyketidesynthasespecificity are severely limited to only a small