TY - JOUR TI - Analysis of the PcrA-RNA polymerase complex reveals a helicase interaction motif and a role for PcrA/UvrD helicase in the suppression of R-loops AU - Urrutia-Irazabal, Inigo AU - Ault, James R AU - Sobott, Frank AU - Savery, Nigel J AU - Dillingham, Mark S A2 - Spies, Maria A2 - Wolberger, Cynthia VL - 10 PY - 2021 DA - 2021/07/19 SP - e68829 C1 - eLife 2021;10:e68829 DO - 10.7554/eLife.68829 UR - https://doi.org/10.7554/eLife.68829 AB - The PcrA/UvrD helicase binds directly to RNA polymerase (RNAP) but the structural basis for this interaction and its functional significance have remained unclear. In this work, we used biochemical assays and hydrogen-deuterium exchange coupled to mass spectrometry to study the PcrA-RNAP complex. We find that PcrA binds tightly to a transcription elongation complex in a manner dependent on protein:protein interaction with the conserved PcrA C-terminal Tudor domain. The helicase binds predominantly to two positions on the surface of RNAP. The PcrA C-terminal domain engages a conserved region in a lineage-specific insert within the β subunit which we identify as a helicase interaction motif present in many other PcrA partner proteins, including the nucleotide excision repair factor UvrB. The catalytic core of the helicase binds near the RNA and DNA exit channels and blocking PcrA activity in vivo leads to the accumulation of R-loops. We propose a role for PcrA as an R-loop suppression factor that helps to minimize conflicts between transcription and other processes on DNA including replication. KW - helicase KW - transcription KW - R-loop KW - replication-transcription conflict KW - HDX-MS KW - DNA repair JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -