The paper by Hao Li and colleagues is fascinating. The use of the term
"designability" is a unfortunate-with its connotations of rationality or
directedness. I think the paper provides a useful corrollary of a possible
evolutionary process. One can imagine all the random amino acid sequences
in the primordial soup 'finding' or 'falling' into a limited number of
stable primordial structures. Natural selection then works with these
primordial structures to introduce functionality. Maybe we should talk
about findable rather than designable structures.
We could conceive of stable structures that are not designable (or
findable?) in nature, since only certain folding pathways are possible or
impassable transition states may be involved.The only thing I was concerned
about with the paper was that they start with the assumption that all
51,704 structures are possible. Whereas in reality there will be barriers
in the folding pathways to some of the stable structures that can be
computer generated. However I suppose that would simply place additional
limits on the number of designable structures and doesnt really change the
main argument of the paper- any comment?
Dr. Ross Barnard BSc,BSc(hons),PhD,PGDipEd.
Senior Research Fellow
CRC for Diagnostic Technologies
Queensland University of Technology
Gardens Point Phone:61-7-3864-5213
Brisbane FAX:61-7-3864-2553
Qld 4001 e-mail:r.barnard@qut.edu.au
Australia.
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