Vaisius A C, Wieland T
Biochemistry. 1982 Jun 22;21(13):3097-101. doi: 10.1021/bi00256a010.
The template-directed synthesis of a single phosphodiester bond by highly purified calf thymus RNA polymerase B is not inhibited by high concentrations of alpha-amanitin (10(-6) M). However, a subsequent internucleotide bond is not synthesized in the presence of alpha-amanitin. These results suggest that translocation of the nascent RNA and RNA polymerase B along the DNA template is the enzymatic process inhibited by alpha-amanitin. It is also shown that the formation of a single phosphodiester bond by RNA polymerase B results in a stable ternary transcription complex, i.e., between the enzyme, the DNA, and the nascent RNA. Under reaction conditions which normally favor the elongation of RNA, the transcriptional process is arrested at initiation by alpha-amanitin. Such ternary initiation complexes have been isolated by agarose gel electrophoresis.
高纯度小牛胸腺RNA聚合酶B进行的模板导向的单个磷酸二酯键合成不受高浓度α-鹅膏蕈碱（10^(-6) M）的抑制。然而，在α-鹅膏蕈碱存在的情况下，随后的核苷酸间键无法合成。这些结果表明，新生RNA和RNA聚合酶B沿DNA模板的易位是受α-鹅膏蕈碱抑制的酶促过程。还表明，RNA聚合酶B形成单个磷酸二酯键会导致形成稳定的三元转录复合物，即酶、DNA和新生RNA之间的复合物。在通常有利于RNA延伸的反应条件下，转录过程在起始阶段被α-鹅膏蕈碱阻断。这种三元起始复合物已通过琼脂糖凝胶电泳分离出来。
