The effect of ionic and temperature shifts used for in vitro ribosome subunit reconstitution upon the large molecular weight ribosomal ribonucleic acids.

ABSTRACT

The behaviour of purified, intact preparations of 16 S and 23 S rRNAs has been studied in their respective ribosome subunit reconstitution systems by means of sedimentation and electrophoretic analysis. Both species undergo profound conformation changes to more compact species at the temperatures and ionic conditions commonly agreed for their reconstitution into ribosome subunits. The 16 S rRNA undergoes a complete conformation change over the input range of concentration used, whereas the change for 23 S rRNA is incomplete for inputs above 1.5 mg X ml-1. Intact 23 S rRNA is also required and some preparations recommended for r-protein binding studies do not meet this requirement for reconstitution. These observations are discussed in relation to the overall effectiveness of ribosome subunit reconstitution systems.