Download MendeleyCrystal Structure of Mil (Mth680): Internal Duplication and Similarity between the Imp4/Brix Domain and the Anticodon-Binding Domain of Class Iia Aminoacyl-tRNA Synthetases
Ng, C.L., Waterman, D., Koonin, E.V., Antson, A.A., Ortiz-Lombardia, M.(2005) EMBO Rep 6: 140
- PubMed: 15654320
- DOI: https://doi.org/10.1038/sj.embor.7400328
- Primary Citation of Related Structures:
1W94 - PubMed Abstract:
Proteins of the Imp4/Brix superfamily are involved in ribosomal RNA processing, an essential function in all cells. We report the first structure of an Imp4/Brix superfamily protein, the Mil (for Methanothermobacter thermautotrophicus Imp4-like) protein (gene product Mth680), from the archaeon M. thermautotrophicus. The amino- and carboxy-terminal halves of Mil show significant structural similarity to one another, suggesting an origin by means of an ancestral duplication. Both halves show the same fold as the anticodon-binding domain of class IIa aminoacyl-tRNA synthetases, with greater conservation seen in the N-terminal half. This structural similarity, together with the charge distribution in Mil, suggests that Imp4/Brix superfamily proteins could bind single-stranded segments of RNA along a concave surface formed by the N-terminal half of their beta-sheet and a central alpha-helix. The crystal structure of Mil is incompatible with the presence, in the Imp4/Brix domain, of a helix-turn-helix motif that was proposed to comprise the RNA-binding moiety of the Imp4/Brix proteins.
Organizational Affiliation:
York Structural Biology Laboratory, Chemistry Department, University of York, York YO10 5YW, UK.
