The Lyngbyatoxin Biosynthetic Assembly Line: Chain Release by Four-Electron Reduction of a Dipeptidyl Thioester to the Corresponding Alcohol
摘要:
In comparison with the large number of nonribosomal peptide synthetases (NRPSs) that release their peptide products by hydrolytic cleavage of the peptide carrier Protein (PCP) bound thioester, there are relatively few NRPSs that have been shown to use a nicotinamide cofactor to reduce this PCP-peptidyl thioester to an aldehyde or imine moiety, This work describes the first example of a reductase domain within a NRPS scaffold shown to reduce a PCP-pepbdyl thioester to the corresponding primary alcohol, via an aldehyde intermediate, using two equivalents of reduced nicotinamide adenine dinucleotide phosphate (NADPH). By employing a ketone mimic of the aldehyde intermediate, as well as a specifically deuterated NADPH, it was further demonstrated that the pro-S hydride of the cofactor is transferred to the re face of the carbonyl group.
Enzymatic Production of (−)-Indolactam V by LtxB, a Cytochrome P450 Monooxygenase
作者:Minh U. Huynh、Matthew C. Elston、Nick M. Hernandez、David B. Ball、Shin-ichiro Kajiyama、Kazuhiro Irie、William H. Gerwick、Daniel J. Edwards
DOI:10.1021/np900481a
日期:2010.1.22
The P450 cytochrome monooxygenase gene, ltxB, was cloned and overexpressed in Escherichia coli as a 6xHis-taoged protein. The resulting recombinant LtxB was purified by Ni-NTA affinity chromatography and characterized biochemically. Purified LtxB demonstrated typical cytochrome P450 spectroscopic properties including substrate-induced transition from a low-spin (lambda(max) = 414 nm) to high-spin state (lambda(max) = 386 nm) upon incubation with N-methyl-L-valyl-L-tryptophanol. The catalytic activity of LtxB was verified by demonstrating the oxidation/cyclization of N-methyl-L-valyl-L-tryptophanol to (-)-indolactam V. LtxB shows a relaxed specificity for analogue substrates in which the valyl group is substituted for other aliphatic groups. The relaxed substrate specificity of LtxB, along with the relaxed specificity of the prenyltransferase, LtxC, allowed for the enzymatic production of a series of (-)-indolactam V and lyngbyatoxin analogues.
The Lyngbyatoxin Biosynthetic Assembly Line: Chain Release by Four-Electron Reduction of a Dipeptidyl Thioester to the Corresponding Alcohol
作者:Jay A. Read、Christopher T. Walsh
DOI:10.1021/ja077374d
日期:2007.12.1
In comparison with the large number of nonribosomal peptide synthetases (NRPSs) that release their peptide products by hydrolytic cleavage of the peptide carrier Protein (PCP) bound thioester, there are relatively few NRPSs that have been shown to use a nicotinamide cofactor to reduce this PCP-peptidyl thioester to an aldehyde or imine moiety, This work describes the first example of a reductase domain within a NRPS scaffold shown to reduce a PCP-pepbdyl thioester to the corresponding primary alcohol, via an aldehyde intermediate, using two equivalents of reduced nicotinamide adenine dinucleotide phosphate (NADPH). By employing a ketone mimic of the aldehyde intermediate, as well as a specifically deuterated NADPH, it was further demonstrated that the pro-S hydride of the cofactor is transferred to the re face of the carbonyl group.
Exploiting a C–N Bond Forming Cytochrome P450 Monooxygenase for C–S Bond Formation
C-Sbond formation reactions are widely distributed in the biosynthesis of biologically active molecules, and thus have received much attention over the past decades. Herein, we report intramolecular C-Sbond formation by a P450 monooxygenase, TleB, which normally catalyzes a C-Nbond formation in teleocidin biosynthesis. Based on the proposed reaction mechanism of TleB, a thiol-substituted substrate