title: Solution structure of a SRP19 binding domain in human SRP RNA.
abstract: Assembly of the human signal recognition particle (SRP) requires SRP19 protein to bind to helices 6 and 8 of SRP RNA. In the present study, structure of a 29-mer RNA composing the SRP19 binding site in helix 6 was determined by NMR spectroscopy. The two A:C mismatches were continuously stacked to each other and formed wobble type A:C base pairs. The GGAG tetraloop in helix 6 was found to adopt a similar conformation to that of GNRA tetraloop, suggesting that these tetraloops are included in an extensive new motif GNRR. Compared with the crystal structure of helix 6 in complex with SRP19 determined previously, the GGAG tetraloop in the complex was found to adopt a similar conformation to the free form, although the loop structure becomes more open upon SRP19 binding. Thus, SRP19 is thought to recognize the overall fold of the GGAG loop.
authors.affiliation: Department of Industrial Chemistry, Faculty of Engineering, Chiba Institute of Technology, Narashino, Chiba 275-0016, Japan.
authors.forename: Taiichi
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Morita
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Tabata
authors.forename: Kouji
authors.initials: K
authors.lastname: Nakamura
authors.forename: Gota
authors.initials: G
authors.lastname: Kawai
mesh_terms: D001665:Binding Sites; D006801:Humans; D008958:Models, Molecular; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D020733:RNA, Small Cytoplasmic / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018271:Signal Recognition Particle / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: C115990:7SL RNA; D020733:RNA, Small Cytoplasmic; C117074:SRP19 protein, human; D018271:Signal Recognition Particle