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Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events
Published on: May 13, 2019
Structure of human mitochondrial RNA polymerase elongation complex
Kathrin Schwinghammer1, Alan C M Cheung, Yaroslav I Morozov
1Gene Center, Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany.
Nature Structural & Molecular Biology
|October 8, 2013
Summary
The crystal structure of human mitochondrial RNA polymerase (mtRNAP) reveals its unique elongation mechanism. Unlike T7 RNAP, mtRNAP elongates without refolding, with RNA exiting toward its distinctive PPR domain.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- Human mitochondrial RNA polymerase (mtRNAP) is essential for mitochondrial gene expression.
- Understanding its structure and function is crucial for deciphering mitochondrial biology and associated diseases.
Purpose of the Study:
- To determine the crystal structure of the human mtRNAP transcription elongation complex.
- To elucidate the structural basis of mtRNAP's unique elongation mechanism.
Main Methods:
- X-ray crystallography at 2.65-Å resolution.
- Structural comparison with bacteriophage T7 RNA polymerase (T7 RNAP).
Main Results:
- The structure reveals a 9-bp DNA-RNA hybrid and flanking DNA in the elongation complex.
- mtRNAP adopts an intermediary conformation for elongation, unlike the refolding required by T7 RNAP.
- A unique RNA exit channel directs the nascent RNA toward the pentatricopeptide repeat (PPR) domain.
Conclusions:
- Human mtRNAP utilizes a distinct mechanism for transcription elongation compared to distantly related RNAPs.
- The PPR domain plays a significant role in mtRNAP function, potentially in RNA binding or processing.
- The findings provide insights into the structural basis of mitochondrial transcription regulation.
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