Interaction of RNA polymerase II fork loop 2 with downstream non-template DNA regulates transcription elongation.

ABSTRACT: Fork loop 2 is a small semiconservative segment of the larger fork domain in the second largest Rpb2 subunit of RNA polymerase II (Pol II). This flexible loop, juxtaposed at the leading edge of transcription bubble, has been proposed to participate in DNA strand separation, translocation along DNA, and NTP loading to Pol II during elongation. Here we show that the Rpb2 mutant carrying a deletion of the flexible part of the loop is not lethal in yeast. The mutation exhibits no defects in DNA melting and translocation in vitro but confers a moderate decrease of the catalytic activity of the enzyme caused by the impaired sequestration of the NTP substrate in the active center prior to catalysis. In the structural model of the Pol II elongation complex, fork loop 2 directly interacts with an u

SUBMITTER: Kireeva ML 

PROVIDER: S-EPMC3162450 | biostudies-literature | 2011 Sep

REPOSITORIES: biostudies-literature