7a8p
Structure of human mitochondrial RNA polymerase in complex with IMT inhibitor.Structure of human mitochondrial RNA polymerase in complex with IMT inhibitor.
Structural highlights
Function[RPOM_HUMAN] DNA-dependent RNA polymerase catalyzes the transcription of mitochondrial DNA into RNA using the four ribonucleoside triphosphates as substrates.[1] Publication Abstract from PubMedAltered expression of mitochondrial DNA (mtDNA) occurs in ageing and a range of human pathologies (for example, inborn errors of metabolism, neurodegeneration and cancer). Here we describe first-in-class specific inhibitors of mitochondrial transcription (IMTs) that target the human mitochondrial RNA polymerase (POLRMT), which is essential for biogenesis of the oxidative phosphorylation (OXPHOS) system(1-6). The IMTs efficiently impair mtDNA transcription in a reconstituted recombinant system and cause a dose-dependent inhibition of mtDNA expression and OXPHOS in cell lines. To verify the cellular target, we performed exome sequencing of mutagenized cells and identified a cluster of amino acid substitutions in POLRMT that cause resistance to IMTs. We obtained a cryo-electron microscopy (cryo-EM) structure of POLRMT bound to an IMT, which further defined the allosteric binding site near the active centre cleft of POLRMT. The growth of cancer cells and the persistence of therapy-resistant cancer stem cells has previously been reported to depend on OXPHOS(7-17), and we therefore investigated whether IMTs have anti-tumour effects. Four weeks of oral treatment with an IMT is well-tolerated in mice and does not cause OXPHOS dysfunction or toxicity in normal tissues, despite inducing a strong anti-tumour response in xenografts of human cancer cells. In summary, IMTs provide a potent and specific chemical biology tool to study the role of mtDNA expression in physiology and disease. Small-molecule inhibitors of human mitochondrial DNA transcription.,Bonekamp NA, Peter B, Hillen HS, Felser A, Bergbrede T, Choidas A, Horn M, Unger A, Di Lucrezia R, Atanassov I, Li X, Koch U, Menninger S, Boros J, Habenberger P, Giavalisco P, Cramer P, Denzel MS, Nussbaumer P, Klebl B, Falkenberg M, Gustafsson CM, Larsson NG Nature. 2020 Dec;588(7839):712-716. doi: 10.1038/s41586-020-03048-z. Epub 2020, Dec 16. PMID:33328633[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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OCA- DNA-directed RNA polymerase
- Large Structures
- Atanassov, I
- Bergbrede, T
- Bonekamp, N
- Boros, J
- Choidas, A
- Cramer, P
- Denzel, M
- Falkenberg, M
- Felser, A
- Giavalisco, P
- Gustafsson, C M
- Habenberger, P
- Hillen, H S
- Horn, M
- Klebl, B
- Koch, U
- Larsson, N G
- Li, X
- Lucrezia, R di
- Menninger, S
- Nussbaumer, P
- Peter, B
- Unger, A
- Inhibitor
- Mitochondria
- Polymerase
- Transcription