Structural basis of transcription: RNA polymerase II substrate binding and metal coordination using a free-electron laser.

ABSTRACT: Catalysis and translocation of multisubunit DNA-directed RNA polymerases underlie all cellular mRNA synthesis. RNA polymerase II (Pol II) synthesizes eukaryotic pre-mRNAs from a DNA template strand buried in its active site. Structural details of catalysis at near-atomic resolution and precise arrangement of key active site components have been elusive. Here, we present the free-electron laser (FEL) structures of a matched ATP-bound Pol II and the hyperactive Rpb1 T834P bridge helix (BH) mutant at the highest resolution to date. The radiation-damage-free FEL structures reveal the full active site interaction network, including the trigger loop (TL) in the closed conformation, bonafide occupancy of both site A and B Mg²⁺, and, more importantly, a putative third (site C) Mg²⁺

SUBMITTER: Lin G 

PROVIDER: S-EPMC11388330 | biostudies-literature | 2024 Sep

REPOSITORIES: biostudies-literature