title: Structural basis for recognition of 2',5'-linked oligoadenylates by human ribonuclease L.
abstract: An interferon-induced endoribonuclease, ribonuclease L (RNase L), is implicated in both the molecular mechanism of action of interferon and the fundamental control of RNA stability in mammalian cells. RNase L is catalytically active only after binding to an unusual activator molecule containing a 5'-phosphorylated 2',5'-linked oligoadenylate (2-5A), in the N-terminal half. Here, we report the crystal structure of the N-terminal ankyrin repeat domain (ANK) of human RNase L complexed with the activator 2-5A. This is the first structural view of an ankyrin repeat structure directly interacting with a nucleic acid, rather than with a protein. The ANK domain folds into eight ankyrin repeat elements and forms an extended curved structure with a concave surface. The 2-5A molecule is accommodated at a concave site and directly interacts with ankyrin repeats 2-4. Interestingly, two structurally equivalent 2-5A binding motifs are found at repeats 2 and 4. The structural basis for 2-5A recognition by ANK is essential for designing stable 2-5As with a high likelihood of activating RNase L.
authors.affiliation: School of Pharmaceutical Sciences, Showa University, Hatanodai, Shinagawa-ku, Tokyo, Japan. ntanaka@pharm.showa-u.ac.jp
authors.forename: Nobutada
authors.initials: N
authors.lastname: Tanaka
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nakanishi
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kusakabe
authors.forename: Yoshikuni
authors.initials: Y
authors.lastname: Goto
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kitade
authors.forename: Kazuo T
authors.initials: KT
authors.lastname: Nakamura
mesh_terms: D000227:Adenine Nucleotides / Q000737:chemistry* / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017487:Ankyrins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016384:Consensus Sequence; D018360:Crystallography, X-Ray; D019281:Dimerization; D004722:Endoribonucleases / Q000737:chemistry* / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D006801:Humans; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009843:Oligoribonucleotides / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D013329:Structure-Activity Relationship; D014867:Water / Q000737:chemistry
chemical_list: D000227:Adenine Nucleotides; D017487:Ankyrins; D009843:Oligoribonucleotides; D014867:Water; C023505:2',5'-oligoadenylate; D004722:Endoribonucleases; C031956:2-5A-dependent ribonuclease