Holloway P, Knoke K L, Trevors J T, Lee H
Department of Biology, University of Winnipeg, Winnipeg, Manitoba, Canada, R3B 2E9.
Biotechnol Bioeng. 1998 Aug 20;59(4):520-3.
We attempted to expand the range of chlorinated solvents degraded by Xanthobacter autotrophicus GJ10 to include trichloroethylene by the rational modification of the enzyme haloalkane dehalogenase. The amino acids Phe164, Asp170, Phe172 and Trp175 were individually replaced with alanine by site-directed mutagenesis. All substitutions produced enzymes with lower than wild type activity with 1,2-dichloroethane. The Phe164Ala and Asp170Ala mutants were 3 and 2 times more active than was the wild type enzyme in dechlorinating 1,6-dichlorohexane. The Asp170Ala mutant resembled the wild type enzyme in its relative activity against longer chain substrates. No mutant was active with trichloroethylene.
我们试图通过对卤代烷脱卤酶进行合理改造，来扩大自养黄色杆菌GJ10降解的氯化溶剂范围，使其包括三氯乙烯。通过定点诱变，将氨基酸苯丙氨酸164、天冬氨酸170、苯丙氨酸172和色氨酸175分别替换为丙氨酸。所有替换产生的酶对1,2 - 二氯乙烷的活性均低于野生型。苯丙氨酸164丙氨酸和天冬氨酸170丙氨酸突变体在使1,6 - 二氯己烷脱氯方面的活性分别是野生型酶的3倍和2倍。天冬氨酸170丙氨酸突变体对较长链底物的相对活性与野生型酶相似。没有突变体对三氯乙烯具有活性。
