Synthesis and Biochemical Analysis of Complex Chain-Elongation Intermediates for Interrogation of Molecular Specificity in the Erythromycin and Pikromycin Polyketide Synthases
摘要:
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.
Synthesis and Biochemical Analysis of Complex Chain-Elongation Intermediates for Interrogation of Molecular Specificity in the Erythromycin and Pikromycin Polyketide Synthases
摘要:
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.
Highly Efficient Nickel-Catalyzed Cross-Coupling of Succinic and Glutaric Anhydrides with Organozinc Reagents
作者:Eric A. Bercot、Tomislav Rovis
DOI:10.1021/ja044588b
日期:2005.1.1
introduction of molecular complexity through the use of functionalized coupling partners. Regioselective alkylation of an unsymmetrical succinic anhydride and a profound effect of pendent coordinating olefins on reaction rate suggest a mechanism involving discrete oxidative addition of the nickel complex into the cyclicanhydride followed by a transmetalation event.
Rhodium-Catalyzed Enantioselective Desymmetrization of <i>meso</i>-3,5-Dimethyl Glutaric Anhydride: A General Strategy to <i>syn</i>-Deoxypolypropionate Synthons
作者:Matthew J. Cook、Tomislav Rovis
DOI:10.1021/ja073269s
日期:2007.8.1
A rhodium phosphinooxazoline system allows for an efficient enantioselectivedesymmetrization of dimethyl glutaric anhydride. Both commercially available and in situ generated sp3-organozinc nucleophiles couple efficiently in high enantiomeric excess. This chemistry has also been extended to other 3,5-disubstituted anhydrides, and further elaboration has enabled the synthesis of potentially useful
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.