Structural highlights
Function
MFD_ECOLI Couples transcription and DNA repair by recognizing RNA polymerase (RNAP) stalled at DNA lesions. Mediates ATP-dependent release of RNAP and its truncated transcript from the DNA, and recruitment of nucleotide excision repair machinery to the damaged site. Can also dissociate RNAP that is blocked by low concentration of nucleoside triphosphates or by physical obstruction, such as bound proteins. In addition, can rescue arrested complexes by promoting forward translocation. Has ATPase activity, which is required for removal of stalled RNAP, but seems to lack helicase activity. May act through a translocase activity that rewinds upstream DNA, leading either to translocation or to release of RNAP when the enzyme active site can not continue elongation.[1] [2] [3] [4] [5]
Publication Abstract from PubMed
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 (ECs). 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.
Structural basis for transcription complex disruption by the Mfd translocase.,Kang JY, Llewellyn E, Chen J, Olinares PDB, Brewer J, Chait BT, Campbell EA, Darst SA Elife. 2021 Jan 22;10. pii: 62117. doi: 10.7554/eLife.62117. PMID:33480355[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Selby CP, Sancar A. Molecular mechanism of transcription-repair coupling. Science. 1993 Apr 2;260(5104):53-8. PMID:8465200
- ↑ Selby CP, Sancar A. Structure and function of transcription-repair coupling factor. I. Structural domains and binding properties. J Biol Chem. 1995 Mar 3;270(9):4882-9. PMID:7876261
- ↑ Selby CP, Sancar A. Structure and function of transcription-repair coupling factor. II. Catalytic properties. J Biol Chem. 1995 Mar 3;270(9):4890-5. PMID:7876262
- ↑ Park JS, Marr MT, Roberts JW. E. coli Transcription repair coupling factor (Mfd protein) rescues arrested complexes by promoting forward translocation. Cell. 2002 Jun 14;109(6):757-67. PMID:12086674
- ↑ Murphy MN, Gong P, Ralto K, Manelyte L, Savery NJ, Theis K. An N-terminal clamp restrains the motor domains of the bacterial transcription-repair coupling factor Mfd. Nucleic Acids Res. 2009 Oct;37(18):6042-53. Epub 2009 Aug 21. PMID:19700770 doi:10.1093/nar/gkp680
- ↑ Kang JY, Llewellyn E, Chen J, Olinares PDB, Brewer J, Chait BT, Campbell EA, Darst SA. Structural basis for transcription complex disruption by the Mfd translocase. Elife. 2021 Jan 22;10. pii: 62117. doi: 10.7554/eLife.62117. PMID:33480355 doi:http://dx.doi.org/10.7554/eLife.62117
