eddy@boulder.UUCP (04/07/87)
>> information is at the DNA level. >use of the term "catalytic RNAs" to describe those RNA molecules (e.g. >the Tetrahymena rRNA) which mediate their own splicing in vitro. This >bastardization of the term catalysis has unfortunately infiltrated many >of our scientific journals. >(Dizzy cites known examples of catalytic RNA's, which are few) >Self-splicing RNAs are NOT catalytic. More nit-picking from me, I'm afraid. While you're entirely right, Dizzy, I like to dream. Catalytic RNA's have a certain appeal, from an evolutionary standpoint, since having 'ribozymes' solves the 'chicken and the egg' problem of which came first, the RNA or the protein. Thus is it is interesting to note the involvement of RNA in many catalytic ribonucleoprotein complexes (snRNP's, hnRNP's, signal recognition particle, and of course ribosomes.) While proteins are intimate parts of these complexes, it is unknown (to me) how much of a catalytic role the RNA part plays. For instance, the hypothetical enzyme peptidyl transferase (makes peptide bonds in association with the ribosome) has not yet been found to my knowledge. It is a possibility that the rRNA is fulfilling this catalytic role. In short, catalytic RNA is a new thing to molecular biology, a very radical idea. While the list of proven catalytic RNA's is short for now, I wouldn't bet that we've found many at all. - Sean Eddy - Dept. of Molecular, Cellular, Developmental Biology - Univ. of Colorado, Boulder; Boulder, CO 80309 - - "Ph.D.'s are for suckers." -- from 'Ask Mr. Science'