Structural basis for transcription complex disruption by the Mfd translocase
- The Rockefeller University, United States
Abstract
Transcription-coupled repair (TCR) is a sub-pathway of nucleotide excision repair (NER) that preferentially removes lesions from the template-strand (t-strand) that stall RNA polymerase (RNAP) elongation complexes (EC). Mfd mediates TCR in bacteria by removing the stalled RNAP concealing the lesion and recruiting Uvr(A)BC. We used cryo-electron microscopy to visualize Mfd engaging with a stalled EC and attempting to dislodge the RNAP. We visualized seven distinct Mfd-EC complexes in both ATP and ADP-bound states. The structures explain how Mfd is remodeled from its repressed conformation, how the UvrA-interacting surface of Mfd is hidden during most of the remodeling process to prevent premature engagement with the NER pathway, how Mfd alters the RNAP conformation to facilitate disassembly, and how Mfd forms a processive translocation complex after dislodging the RNAP. Our results reveal an elaborate mechanism for how Mfd kinetically discriminates paused from stalled ECs and disassembles stalled ECs to initiate TCR.
Data availability
The cryo-EM density maps have been deposited in the EMDataBank under accession codes EMD-21996 [L1(ATP)], EMD-22006 [L2(ADP)], EMD-22012 [I(ATP)], EMD-22039 [II(ATP)], EMD-22043 [III(ADP)], EMD-22044 [IV(ADP)], and EMD-22045 [V(ATP)]. The atomic coordinates have been deposited in the Protein Data Bank under accession codes 6X26 [L1(ATP)], 6X2F [L2(ADP)], 6X2N [I(ATP)], 6X43 [II(ATP)], 6X4W [III(ADP)], 6XYY [IV(ADP)], and 6X5Q [V(ATP)].
Article and author information
Author details
Funding
National Institute of General Medical Sciences (P41 GM109824)
- Brian T Chait
National Institute of General Medical Sciences (P41 GM103314)
- Brian T Chait
National Institute of General Medical Sciences (R01 GM114450)
- Elizabeth A Campbell
National Institute of General Medical Sciences (R35 GM118130)
- Seth A Darst
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2021, Kang et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Structural basis for transcription complex disruption by the Mfd translocase
eLife 10:e62117.
https://doi.org/10.7554/eLife.62117
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