8QN8

Mycobacterium smegmatis RNA polymerase in complex with HelD, SigA and RbpA in State II

Summary for 8QN8

• Entry DOI: 10.2210/pdb8qn8/pdb
• Related: 8Q3I
• EMDB information: 18511
• Descriptor: DNA-directed RNA polymerase subunit alpha, DNA-directed RNA polymerase subunit beta, DNA-directed RNA polymerase subunit beta', ... (9 entities in total)
• Functional Keywords: held, rna polymerase, transcription initiation, mycobacteria, transcription, rifampicin resistance
• Biological source: Mycolicibacterium smegmatis MC2 155; More
• Total number of polymer chains: 8
• Total formula weight: 508962.16

Authors

Koval, T.,Krasny, L.,Dohnalek, J.,Kouba, T. (deposition date: 2023-09-25, release date: 2024-10-02, Last modification date: 2024-12-11)

Primary citation

Koval, T.,Borah, N.,Sudzinova, P.,Brezovska, B.,Sanderova, H.,Vankova Hausnerova, V.,Krenkova, A.,Hubalek, M.,Trundova, M.,Adamkova, K.,Duskova, J.,Schwarz, M.,Wiedermannova, J.,Dohnalek, J.,Krasny, L.,Kouba, T.
Mycobacterial HelD connects RNA polymerase recycling with transcription initiation.
Nat Commun, 15:8740-8740, 2024

PubMed Abstract: Mycobacterial HelD is a transcription factor that recycles stalled RNAP by dissociating it from nucleic acids and, if present, from the antibiotic rifampicin. The rescued RNAP, however, must disengage from HelD to participate in subsequent rounds of transcription. The mechanism of release is unknown. We show that HelD from Mycobacterium smegmatis forms a complex with RNAP associated with the primary sigma factor σ and transcription factor RbpA but not CarD. We solve several structures of RNAP-σ-RbpA-HelD without and with promoter DNA. These snapshots capture HelD during transcription initiation, describing mechanistic aspects of HelD release from RNAP and its protective effect against rifampicin. Biochemical evidence supports these findings, defines the role of ATP binding and hydrolysis by HelD in the process, and confirms the rifampicin-protective effect of HelD. Collectively, these results show that when HelD is present during transcription initiation, the process is protected from rifampicin until the last possible moment.

PubMed: 39384756
DOI: 10.1038/s41467-024-52891-5

Experimental method

ELECTRON MICROSCOPY (3.14 Å)