Re: Science, Aug 2nd

Dr. T.P.Walsh (
Tue, 20 Aug 1996 08:15:02 +1000 (EST)

Interesting paper with possible implications for many fields. For example,
if possibilities are limited by designability, does it mean that there will
be some structures and activities that will never be able to be made?

Christoph Weber's comment
>This reminds me of the old question:
>"Why are proteins so large?"
>My long-time suspicion was to "provide a buffer" against the cumulative effect
>of mutations and to "suppress unwanted side-reactions" (or whatever 'reaction'
>may mean in the context of non-enzymes).
>The question has never been adequately answered, as far as I know.
may be relevant to the editorial's "direct association of designability to
the structural elements such as superfolds". The large size of proteins may
be dictated to a degree by limited "associability" of the smaller modules.

In a slight aside, it is worth noting that a number of proteins have
multiple "functions". For example, several of the classic glycolytic
enzymes can bundle an cross-link actin filaments. There is even recent
evidence that some may have capping and severing activity as well. A lot of
the "extra" surface of proteins may have to do with their additional
functions outside the category in which we have pigeon-holed them.

Good discussion


Terry Walsh PhD
Program Leader CRC for Diagnostic Technologies
S/Lecturer Biochemistry & Molecular Biology, School of Life Science
Queensland University of Technology, GPO Box 2434, Brisbane, 4001
AUSTRALIA Phone +61 7 3864 2347 Fax +61 7 3864 1534