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.
使用来自 Neosartorya fischeri 的重组异戊二烯转移酶成功制备了六种 β 配置的反向 C3 异戊二烯化吡咯并 [2,3-b] 吲哚。为此目的,将推定的异戊烯基转移酶基因NFIA_074280(本文称为cdpC3PT)克隆到pQE60中并在大肠杆菌中过表达。将过量产生的 His6-CdpC3PT 纯化至接近均质,并在二甲基烯丙基二磷酸 (DMAPP) 存在下与五种含环状色氨酸的二肽一起孵育。所有底物均被 CdpC3PT 接受并转化为反向 C3-异戊二烯化吡咯并[2,3-b]吲哚。以环-L-色氨酸-L-色氨酸为底物,得到单烯化和二烯化衍生物。酶产物的结构通过 HR-ESI-MS、1H 和 13C-NMR 分析以及制备分离后异核多重键关联 (HMBC) 光谱中的长程 1H-13C 连接性得到证实。核欧沃豪瑟效应光谱 (NOESY) 中的 1H-1H 空间相关性用于确定绝对构型。 DMAPP 的 KM 值测定为约 1.5 mM,环状二肽的 KM 值范围为 0.22 至 5.5 mM。周转数 kcat 的范围为 0.023 至 0.098 s±1,特异性常数 kcat/KM 的范围为 14.2 至 122.7 M±1 s±1。与带有α-配置的C3-二甲基烯丙基残基的AnaPT 产物相比,CdpC3PT 产物中的C3-异戊二烯基部分具有β-配置。 CdpC3PT 的发现和表征扩展了化学酶方法在 C3-异戊二烯化衍生物立体定向合成中的用途。