title: RNA recognition by the human U1A protein is mediated by a network of local cooperative interactions that create the optimal binding surface.
abstract: One of the most common structural motifs in RNA-binding proteins is the RNA-binding domain (RBD). These domains share a common alpha/beta sandwich tertiary fold, and are highly conserved, though they bind diverse RNA targets with a wide range of binding affinities. The N-terminal RNA-binding domain (RBD1) of the human U1A protein binds specifically to stem/loop II of the U1 snRNA with sub-nanomolar affinity. Solvent-exposed aromatic residues on the beta-sheet surface are highly conserved among RBD domains; in RBD1, these are Tyr13 and Phe56, with a unique Gln at position 54. Effects of substitutions at these positions were examined using energetic pairwise coupling to describe the communication between these residues in both the free and RNA-bound states of the protein. 15N NMR experiments were used to determine effects of the beta-sheet substitutions on the structural and dynamic properties of this domain. The combination of thermodynamic pairwise coupling and 15N-backbone dynamics provides direct evidence for local cooperative interactions among Y13, Q54, and F56, and a non-conserved loop that directly affect RNA-binding. The results describe how conserved and non-conserved regions of an RBD can communicate with each other to mediate recognition of the RNA.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St Louis, MO, 63110, USA.
authors.forename: J K
authors.initials: JK
authors.lastname: Kranz
authors.forename: K B
authors.initials: KB
authors.lastname: Hall
mesh_terms: D001665:Binding Sites; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D012313:RNA / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D017412:Ribonucleoprotein, U1 Small Nuclear / Q000235:genetics / Q000378:metabolism*; D013816:Thermodynamics
chemical_list: D016601:RNA-Binding Proteins; D017412:Ribonucleoprotein, U1 Small Nuclear; C075339:U1A protein; D012313:RNA