Specific interaction between the self-splicing RNA of Tetrahymena and its guanosine substrate: implications for biological catalysis by RNA.

Splicing of the ribosomal RNA precursor of Tetrahymena has previously been shown to require no protein in vitro; the cleavage-ligation activity is intrinsic to the RNA molecule. Analysis of the reaction kinetics with guanosine, which is a substrate in the reaction, and with several guanosine analogues suggests that guanosine binds to a specific site on the pre-rRNA. It appears that the RNA, like an enzyme, binds its substrate to promote the rate and specificity of a biological reaction.