Low molecular weight ribonucleic acid in rabbit reticulocyte ribosomes

Abstract

A low molecular weight RNA which we call “lRNA” is released from the 30 s ribosomal RNA or the large ribosomal subunit of rabbit reticulocyte ribosomes by treatment which disrupts base pairing. Separation of the two RNA species may occur at a relatively low temperature (43 °C in 0.01 m-phosphate buffer, pH 7.6) indicating that only a small number of bases, not more than about six, are involved in pairing. The fact that the temperature of RNA release from ribosomes is about the same as that from the isolated RNA indicates that ribosomal proteins do not stabilize the interaction between the two RNA species in the ribosome. No ribosomal proteins are released along with RNA. Reassociation of the two RNA chains occurs when they are annealed together from 65 °C in standard saline citrate buffer. Purification of the RNA in amounts sufficient for measurements of its molecular weight, composition and secondary structure, and the results of these studies, are reported.