Download MendeleyCrystal structures of the Arabidopsis thaliana organellar RNA editing factors MORF1 and MORF9.
Haag, S., Schindler, M., Berndt, L., Brennicke, A., Takenaka, M., Weber, G.(2017) Nucleic Acids Res 45: 4915-4928
- PubMed: 28201607
- DOI: https://doi.org/10.1093/nar/gkx099
- Primary Citation of Related Structures:
5MPW, 5MPX, 5MPY - PubMed Abstract:
In flowering plant plastids and mitochondria, multiple organellar RNA editing factor (MORF/RIP) proteins are required at most sites for efficient C to U RNA editing catalyzed by the RNA editosome. MORF proteins harbor a conserved stretch of residues (MORF-box), form homo- and heteromers and interact with selected PPR (pentatricopeptide repeat) proteins, which recognize each editing site. The molecular function of the MORF-box remains elusive since it shares no sequence similarity with known domains. We determined structures of the A. thaliana mitochondrial MORF1 and chloroplast MORF9 MORF-boxes which both adopt a novel globular fold (MORF domain). Our structures state a paradigmatic model for MORF domains and their specific dimerization via a hydrophobic interface. We cross-validate the interface by yeast two-hybrid studies and pulldown assays employing structure-based mutants. We find a structural similarity of the MORF domain to an N-terminal ferredoxin-like domain (NFLD), which confers RNA substrate positioning in bacterial 4-thio-uracil tRNA synthetases, implying direct RNA contacts of MORF proteins during RNA editing. With the MORF1 and MORF9 structures we elucidate a yet unknown fold, corroborate MORF interaction studies, validate the mechanism of MORF multimerization by structure-based mutants and pave the way towards a complete structural characterization of the plant RNA editosome.
Organizational Affiliation:
Molekulare Botanik, Universität Ulm, 89069 Ulm, Germany.
