Characterization of the binding of rat liver ribosomal proteins L6, L7, and L19 to 5 S ribosomal ribonucleic acid.

The binding of rat liver ribosomal proteins L6, L7, and L19 to 5 S rRNA was characterized by nitrocellulose membrane filtration. Binding could be saturated with the three proteins; the apparent association constants (Ka'), measured at 4 degrees C and 22 degrees C, ranged from 1.3 to 6.8 x 10(5) M-1. The molar ratio of ribosomal protein and rRNA in the complex at saturation approximated 1, indicating there is one binding site for each of the three proteins on the nucleic acid. A large number of rat liver ribosomal proteins, including some previously suspected of associating weakly, did not form a complex with 5 S rRNA.