Probing the enantioselectivity of a diverse group of purified cobalt-centred nitrile hydratases
作者:S. van Pelt、M. Zhang、L. G. Otten、J. Holt、D. Y. Sorokin、F. van Rantwijk、G. W. Black、J. J. Perry、R. A. Sheldon
DOI:10.1039/c0ob01067g
日期:——
In this study a diverse range of purified cobalt containing nitrile hydratases (NHases, EC 4.2.1.84) from Rhodopseudomonas palustris HaA2 (HaA2), Rhodopseudomonas palustris CGA009 (009), Sinorhizobium meliloti 1021 (1021), and Nitriliruptor alkaliphilus (iso2), were screened for the first time for their enantioselectivity towards a broad range of chiral nitriles. Enantiomeric ratios of >100 were found for the NHases from HaA2 and CGA009 on 2-phenylpropionitrile. In contrast, the Fe-containing NHase from the well-characterized Rhodococcus erythropolis AJ270 (AJ270) was practically aselective with a range of different α-phenylacetonitriles. In general, at least one bulky group in close proximity to the α-position of the chiral nitriles seemed to be necessary for enantioselectivity with all NHases tested. Nitrile groups attached to a quaternary carbon atom were only reluctantly accepted and showed no selectivity. Enantiomeric ratios of 80 and >100 for AJ270 and iso2, respectively, were found for the pharmaceutical intermediate naproxennitrile, and 3-(1-cyanoethyl)benzoic acid was hydrated to the corresponding amide by iso2 with an enantiomeric ratio of >100.
在本研究中,首次对来自红假单胞菌HaA2(HaA2)、红假单胞菌CGA009(009)、豌豆根瘤菌1021(1021)和嗜碱氮裂解菌(iso2)的多种纯化钴含氮裂解酶(NHases,EC 4.2.1.84)对一系列手性腈的立体选择性进行了筛选。对于2-苯基丙腈,来自HaA2和CGA009的NHases的立体异构比大于100。相比之下,来自已知红球菌AJ270(AJ270)的含铁NHase对一系列不同α-苯基乙腈实际上没有选择性。总的来说,对于所有测试的NHases来说,似乎至少需要一个在α-位附近的大体积基团才能实现立体选择性。连接在四级碳原子上的腈基团仅勉强被接受,并且没有显示出选择性。对于药物中间体萘普生腈,AJ270和iso2的立体异构比分别为80和大于100;iso2还将3-(1-氰乙基)苯甲酸水合为相应的酰胺,立体异构比大于100。