Functional analysis of peptide motif for RNA microhelix binding suggests new family of RNA-binding domains.
RNA microhelices that recreate the acceptor stems of transfer RNAs are charged with specific amino acids. Here we identify a two-helix pair in alanyl-tRNA synthetase that is required for RNA microhelix binding. A single point mutation at an absolutely conserved residue in this motif selectively disrupts RNA binding without perturbation of the catalytic site. These results, and findings of similar motifs in the proximity of the active sites of other tRNA synthetases, suggest that two-helix pairs are widespread and provide a structural framework important for contacts with bound RNA substrates.
Ribas de Pouplana
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The Skaggs Institute for Chemical Biology and Departments of Molecular Biology and Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Buechter
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Sardesai
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Schimmel
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D000412:Alanine-tRNA Ligase / Q000737:chemistry* / Q000235:genetics; D000595:Amino Acid Sequence; D001120:Arginine / Q000737:chemistry; D001224:Aspartic Acid / Q000737:chemistry; D001665:Binding Sites; D017124:Conserved Sequence; D004926:Escherichia coli / Q000201:enzymology; D007700:Kinetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D017433:Protein Structure, Secondary; D012344:RNA, Transfer, Ala / Q000737:chemistry*
D012344:RNA, Transfer, Ala; D001224:Aspartic Acid; D001120:Arginine; D000412:Alanine-tRNA Ligase