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| Title | RNA polymerase inhibitors reveal active-site motions essential for the nucleotide-addition cycle. |
|---|---|
| Journal, issue, pages | bioRxiv, Year 2026 |
| Publish date | Apr 7, 2026 |
Authors | Yukti Dhingra / Robert Landick / Elizabeth A Campbell / Seth A Darst / ![]() |
| PubMed Abstract | The nucleotide-addition cycle (NAC) of multi-subunit DNA-dependent RNA polymerases (RNAPs) involves coordinated conformational changes in conserved active-site structural elements, including the ...The nucleotide-addition cycle (NAC) of multi-subunit DNA-dependent RNA polymerases (RNAPs) involves coordinated conformational changes in conserved active-site structural elements, including the trigger loop (TL). The TL is open (unfolded) in most RNAP structures but can close (fold) in substrate-bound (post- or pre-translocated) states of the RNAP, promoting catalysis. TL closure has been associated with closure of another conserved structural element, the Rim-Helices/F-loop (RH-FL), but the role of the RH-FL in the NAC is unclear. Antibiotic leads CBR9379 and AAP-SO inhibit the and RNAPs, respectively, by binding in a pocket formed by the bridge helix and RH-FL. The precise mechanism of action for these inhibitors is yet to be defined. We present cryo-electron microscopy structures showing that both compounds inhibit the RNAP NAC by preventing RH-FL closure, thereby allosterically destabilizing the closed TL. This work reveals a conserved mechanistic principle of RNAP catalysis across all domains of life and provides new insight for antibiotic design. |
External links | bioRxiv / PubMed:41993335 / PubMed Central |
| Methods | EM (single particle) |
| Resolution | 2.8 - 2.9 Å |
| Structure data | EMDB-75279, PDB-10ma: EMDB-75280, PDB-10mb: EMDB-75281, PDB-10mc: EMDB-75282, PDB-10md: |
| Chemicals | ![]() ChemComp-1N7: ![]() ChemComp-MG: ![]() ChemComp-ZN: ![]() ChemComp-HOH: |
| Source |
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Keywords | Transcription/DNA/RNA / Transcription / DNA/RNA / Nucleotide addition cycle / RNA polymerase / Transcription-DNA-RNA complex |
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