NMR structure of the N-terminal domain of Saccharomyces cerevisiae RNase HI reveals a fold with a strong resemblance to the N-terminal domain of ribosomal protein L9.
In addition to the conserved and well-defined RNase H domain, eukaryotic RNases HI possess either one or two copies of a small N-terminal domain. The solution structure of one of the N-terminal domains from Saccharomyces cerevisiae RNase HI, determined using NMR spectroscopy, is presented. The 46 residue motif comprises a three-stranded antiparallel beta-sheet and two short alpha-helices which pack onto opposite faces of the beta-sheet. Conserved residues involved in packing the alpha-helices onto the beta-sheet form the hydrophobic core of the domain. Three highly conserved and solvent exposed residues are implicated in RNA binding, W22, K38 and K39. The beta-beta-alpha-beta-alpha topology of the domain differs from the structures of known RNA binding domains such as the double-stranded RNA binding domain (dsRBD), the hnRNP K homology (KH) domain and the RNP motif. However, structural similarities exist between this domain and the N-terminal domain of ribosomal protein L9 which binds to 23 S ribosomal RNA.
Evans
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SP
Cambridge Centre for Protein Engineering, Department of Chemistry, Cambridge University, Lensfield Road, Cambridge, CB2 1EW, UK.
Bycroft
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D000595:Amino Acid Sequence; D001483:Base Sequence; D020134:Catalytic Domain / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D016914:Ribonuclease H / Q000737:chemistry* / Q000235:genetics; D012269:Ribosomal Proteins / Q000737:chemistry* / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000201:enzymology* / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D005656:Fungal Proteins; D012269:Ribosomal Proteins; C049650:ribosomal protein L9; D016914:Ribonuclease H; C078856:ribonuclease HI