title: Small-angle X-ray titration of the complex formed between the ribosomal protein S4 and its 16S binding site, S4-RNA: a central core in the 30S subunit.
abstract: X-ray scattering titrations at 21 degree C and in ribosomal reconstitution buffer indicate that the S4-RNA and the protein S4 from a 1:1 complex with a stability constant, log  K approximately 6.5. When the complex forms, there is only a limited change in the scattering curve indicating that S4-RNA essentially retains its conformation during the complex formation. The increase in the gyration radius as a result of the complex formation, delta R = 4 +/- 3 A, as well as the experimental scattering curve of the complex can be explained by models where the protein S4 is supposed to interact with the periphery of the S4-RNA.
mesh_terms: D001665:Binding Sites; D004926:Escherichia coli / Q000648:ultrastructure; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D011487:Protein Conformation; D012335:RNA, Ribosomal; D012269:Ribosomal Proteins; D012270:Ribosomes / Q000648:ultrastructure*; D012542:Scattering, Radiation; D014965:X-Rays
chemical_list: D012335:RNA, Ribosomal; D012269:Ribosomal Proteins