Kostyuk D A, Dragan S M, Lyakhov D L, Rechinsky V O, Tunitskaya V L, Chernov B K, Kochetkov S N
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow.
FEBS Lett. 1995 Aug 7;369(2-3):165-8. doi: 10.1016/0014-5793(95)00732-o.
A mutant T7 RNA polymerase (T7 RNAP) having two amino-acid substitutions (Y639F and S641A) is altered in its specificity towards nucleotide substrates, but is not affected in the specificity of its interaction with promoter and terminator sequences. The mutant enzyme gains the ability to utilize dNTPs and catalyze RNA and DNA synthesis from circular supercoiled plasmid DNA. DNA synthesis can also be initiated from a single stranded template using a DNA primer. Another T7 RNAP mutant having only the single substitution S641A loses RNA polymerase activity but is able to synthesize DNA.
一种具有两个氨基酸取代（Y639F和S641A）的突变型T7 RNA聚合酶（T7 RNAP），其对核苷酸底物的特异性发生了改变，但与启动子和终止子序列相互作用的特异性不受影响。该突变酶获得了利用脱氧核糖核苷三磷酸（dNTPs）并从环状超螺旋质粒DNA催化RNA和DNA合成的能力。DNA合成也可以使用DNA引物从单链模板起始。另一种仅具有单一取代S641A的T7 RNAP突变体丧失了RNA聚合酶活性，但能够合成DNA。
