Open AccessThe Ternary 5‐S RNA Complex of Proteins L18 and L25
Author(s) -
ÖSTERBERG Ragnar
Publication year - 1979
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1979.tb13134.x
Subject(s) - ribosome , rna , ternary complex , ternary operation , radius of gyration , chemistry , crystallography , scattering , gyration , ribosomal rna , titration , physics , biochemistry , mathematics , enzyme , polymer , organic chemistry , geometry , optics , computer science , programming language , gene
The 5‐S RNA (A) and the proteins L18 (B) and L25 (C) from Escherichia coli ribosomes form a ternary complex of the type ABC with a stepwise stability constant, log K 111 ∼6.5. This is indicated from X‐ray scattering titrations recorded at 21°C in ribosomal reconstitutional buffer. When the ternary ABC complex forms there is only a limited change in the scattering curve compared to that of 5‐S RNA, indicating that 5‐S RNA does not undergo a major conformational change during the complex formation. The increase in the radius of gyration from 3.61 nm (5‐S RNA) to 3.95 nm (ABC complex) as well as the experimental scattering curve can be explained by models where it is assumed that the elongated L18 and L25 models are quite far from the electron density centre and where the protein molecules interact mainly with the minor arms of the supposed Y‐shaped 5‐S RNA molecule.