Structural Prediction

[Chuck An]

In article <81181.ewright at fox.nstn.ns.ca>, ewright at FOX.NSTN.NS.CA ("Edwin Wright") says:
>
>The following statement appeared in Nature:
>
>"There are now many examples, in both functionally similar and dissimilar
>proteins, where the sequence similarity is statistically insignificant (less
>than 20%) and yet the same topology is observed." (M. Thornton, T.P. Flores,
>D.T. Jones, M.B. Swindells, Nature, 354, 105, (1991) - p. 106)
>
>If this situation is common, then it seems that notwithstanding functional
>similarity/dissimilarity, topological similarity is dependent on a meta-
>sequential order, not readily apparent at the level of independently
>displayed sequences.  Presumably, this meta-sequential order is governed by
>one of the following possibilities:
>
>1. There is a distinct set of sequences (the basis of which is unknown)
>   responsible for a specific topology.
>
>2. The set of sequences responsible for a specific topology are actually
>   manifesting conserved positions (albeit non-conserved residues) of a
>   single (unknown) meta-sequence.
>
>Is anyone aware of any research with respect to the second possibility?
>
>Regards,
>-------
>Edwin Wright
>85 Spinnaker Drive, A-602
>Halifax, Nova Scotia
>CANADA B3N 3E3
>
>Telephone: (902) 477-5037
>
>Email: ewright at fox.nstn.ns.ca
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I think so. it has been noticed that proteins from different families and with quite
big variation in sequences were found having both local ang gobal structural 
resemblance. they were able to be sort of superimposed on one another. I can't
recall the details.

I wander whether the 3D structures of proteins are the consequences of 
the combination of the amino acid residues, but not necessarily the definite
 permutation of the residues.