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From: eddy@boulder.UUCP
Newsgroups: sci.bio
Subject: catalytic RNA's
Message-ID: <886@sigi.Colorado.EDU>
Date: Tue, 7-Apr-87 13:28:26 EST
Article-I.D.: sigi.886
Posted: Tue Apr  7 13:28:26 1987
Date-Received: Sat, 11-Apr-87 07:23:24 EST
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Reply-To: eddy@beagle.Colorado.EDU (Sean Eddy)
Organization: University of Colorado, Boulder
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>> 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'