Two site-directed mutants of Thr215 were constructed and used to catalyze the epoxidation of styrenes. The expressed con-dition were optimized. The thermal stability of the mutants were investigated,meanwhile,the conversion rate and enantioselective of epoxidation of terminal aromatic alkenes and non-terminal aromatic alkenes were tested. The results showed that the T215V and T215G mutants were similar with the wild type in catalyzing the terminal aromatic alkenes. However,there was difference among the conversion rate and enantioselective of the mutants T215V,T215G and wild type CYP119 catalyzing the non terminal aromatic al-kenes. The T215G mutant was discovered to show highly conversion rate epoxidation of styrenes with up to 99. 6%and enhanced the conversion rate and enantioselective for epoxidation of cis-β-methylstyrene. The mutant T215V was found to reduce the enantioselec-tivity of cis-β-methylstyrenes. The hydrogen-bonding interactions and the chain size of the Thr215 site had certain influence on the epoxidation activity of special substrates.%通过对CYP119过氧化物酶活性中心215位保守苏氨酸的定点突变,研究突变体对催化苯乙烯类似底物环氧化反应的作用效率.考察了CYP119酶215位突变体的热稳定性;端基双键的苯乙烯类似物和非端基双键的β-甲基苯乙烯类似物环氧化反应的转化率和对映选择性.结果表明,CYP119酶突变体T215G和T215V催化端基双键类底物效果与亲本酶类似,而催化非端基双键类底物在转化率和对映选择性上都具有一定变化.突变体T215G催化苯乙烯环氧化反应的转化率高达99.6%.突变体T215G能一定程度提高催化顺式β-甲基苯乙烯环氧化反应的对映选择性和转化率.突变体T215V催化顺式-β-甲基苯乙烯类底物,环氧化反应对映选择性远低于亲本酶和突变体T215G.说明215位苏氨酸的氢键效应和侧链氨基酸大小对CYP119酶催化特定底物的环氧化反应具有一定影响.
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