Structural Basis for Substrate Binding and Selection by Human Mitochondrial RNA Polymerase

Authors

Karl Herbine, Thomas Jefferson UniversityFollow
Ashok Nayak, Thomas Jefferson UniversityFollow
Dmitry Temiakov, Thomas Jefferson UniversityFollow

Document Type

Article

Publication Date

8-20-2024

Comments

This article is the author's final published version in Nature Communications, Volume 15, Issue 1, 2024, Article number 7134.

The published version is available at https://doi.org/10.1038/s41467-024-50817-9.

Copyright © The Author(s) 2024

Abstract

The mechanism by which RNAP selects cognate substrates and discriminates between deoxy and ribonucleotides is of fundamental importance to the fidelity of transcription. Here, we present cryo-EM structures of human mitochondrial transcription elongation complexes that reveal substrate ATP bound in Entry and Insertion Sites. In the Entry Site, the substrate binds along the O helix of the fingers domain of mtRNAP but does not interact with the templating DNA base. Interactions between RNAP and the triphosphate moiety of the NTP in the Entry Site ensure discrimination against nucleosides and their diphosphate and monophosphate derivatives but not against non-cognate rNTPs and dNTPs. Closing of the fingers domain over the catalytic site results in delivery of both the templating DNA base and the substrate into the Insertion Site and recruitment of the catalytic magnesium ions. The cryo-EM data also reveal a conformation adopted by mtRNAP to reject a non-cognate substrate from its active site. Our findings establish a structural basis for substrate binding and suggest a unified mechanism of NTP selection for single-subunit RNAPs.

Recommended Citation

Herbine, Karl; Nayak, Ashok; and Temiakov, Dmitry, "Structural Basis for Substrate Binding and Selection by Human Mitochondrial RNA Polymerase" (2024). Department of Biochemistry and Molecular Biology Faculty Papers. Paper 264.
https://jdc.jefferson.edu/bmpfp/264

Creative Commons License

This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

PubMed ID

39164235

Language

English