α-Amanitin Blocks Translocation by Human RNA Polymerase II

摘要: Our laboratory has developed methods for transient state kinetic analysis of human RNA polymerase II elongation. In these studies, multiple conformations the elongation complex were revealed by their distinct potential and differing dependence on nucleoside triphosphate substrate. Among are that appear to correspond different translocation states DNA template RNA-DNA hybrid. Using α-amanitin as a dynamic probe mechanism, we show most highly poised conformation complex, which interpreted previously posttranslocated state, is selectively resistant inhibition with α-amanitin. Because initially complexes form only single phosphodiester bond before being rendered inactive in following addition cycle, inhibits at each step.