Switching a regular tryptophan <i>C4</i>-prenyltransferase to a reverse tryptophan-containing cyclic dipeptide <i>C3</i>-prenyltransferase by sequential site-directed mutagenesis
作者:Liujuan Zheng、Peter Mai、Aili Fan、Shu-Ming Li
DOI:10.1039/c8ob01735b
日期:——
FgaPT2 from Aspergillus fumigatus catalyzes a regular C4- and its mutant K174A a reverse C3-prenylation of L-tryptophan in the presence of dimethylallyl diphosphate. FgaPT2 also uses tryptophan-containing cyclicdipeptides for C4-prenylation, while FgaPT2_K174A showed almost no activity toward these substrates. In contrast, Arg244 mutants of FgaPT2 accept very well cyclicdipeptides for regular C4-prenylation
在二磷酸二甲基烯丙酯的存在下,烟曲霉的FgaPT2催化了常规的C4-及其突变体K174A的L-色氨酸的反向C3-异戊二烯化。FgaPT2还使用含色氨酸的环状二肽进行C4-异戊二烯化,而FgaPT2_K174A对这些底物几乎没有活性。相反,FgaPT2的Arg244突变体接受非常好的环状二肽以进行规则的C4-异戊二烯化。在这项研究中,我们证明了FgaPT2_K174F,催化定期C3酪氨酸-prenylation,也可以使用环-大号-Trp-大号-Ala,环-大号-Trp-大号-Trp,环-大号-Trp -甘氨酸,环-大号-Trp-大号-Phe,环-大号-Trp-大号-Pro,和环-大号-Trp-大号-Tyr作为底物,但仅活动少。Lys174和Arg244的组合突变显着提高了对这些环状二肽的接受度。除了cyclo - L -Trp- L-Trp,FgaPT2_K174F_R244X(X = L
Preparation of pyrrolo[2,3-b]indoles carrying a β-configured reverse C3-dimethylallyl moiety by using a recombinant prenyltransferase CdpC3PT
作者:Wen-Bing Yin、Xia Yu、Xiu-Lan Xie、Shu-Ming Li
DOI:10.1039/c000587h
日期:——
Six β-configured reversely C3-prenylated pyrrolo[2,3-b]indoles were successfully prepared by using a recombinant prenyltransferase from Neosartorya fischeri. For this purpose, the putative prenyltransferase gene NFIA_074280 (termed herewith cdpC3PT) was cloned into pQE60 and overexpressed in Escherichia coli. The overproduced His6-CdpC3PT was purified to near homogeneity and incubated with five cyclic tryptophan-containing dipeptides in the presence of dimethylallyl diphosphate (DMAPP). All of the substrates were accepted by CdpC3PT and converted to reversely C3-prenylated pyrrolo[2,3-b]indoles. Using cyclo-L-Trp-L-Trp as substrate, both mono- and diprenylated derivatives were obtained. The structures of the enzymatic products were confirmed by HR-ESI-MS, 1H- and 13C-NMR analyses as well as by long-range 1H-13C connectivities in heteronuclear multiple-bond correlation (HMBC) spectra after preparative isolation. 1H-1H spatial correlations in nuclear overhauser effect spectroscopy (NOESY) were used for determination of absolute configuration. The KM values were determined at about 1.5 mM for DMAPP and in the range from 0.22 to 5.5 mM for cyclic dipeptides. The turnover number kcat were found in the range of 0.023 to 0.098 sâ1 and specificity constants kcat/KM from 14.2 to 122.7 Mâ1 sâ1. In contrast to the products of AnaPT bearing α-configured C3-dimethylallyl residues, the C3-prenyl moieties in the products of CdpC3PT have a β-configuration. Discovery and characterisation of CdpC3PT expand the usage of the chemoenzymatic approach for stereospecific synthesis of C3-prenylated derivatives.
Total synthesis of (−)-penicimutanin a and related congeners
作者:Haiyong Yu、Yan Zong、Tao Xu
DOI:10.1039/c9sc05252f
日期:——
The first totalsynthesis of penicimutanin A (1) was achieved within 10 steps (LLS). Key innovations in this synthesis consist of (1) a highly efficient electro-oxidative dearomatization; (2) an unprecedented bisoxirane-directed intermolecular aldol reaction from the sterically hindered face of the ketone and (3) the diastereoselective one-step Meerwein–Eschenmoser–Claisen rearrangement enabling the