Re: "homology / similarity" of proteins

William Pitt (
Fri, 24 May 1996 17:58:26 +0100 (BST)

Dear Sophia,
thanks very much for the information.
Let me think it through. As gene duplication leads to the evolution of
proteins with same fold but with different functions, this suggests that
paralogous proteins are in indeed homologous in structure but with
different functions? I presume speciation is the accumulation of neutral
mutations which I suppose could eventually lead to the proteins in
different structure but the same function (but it seems unlikely?). So I
guess my understanding of what Peer ment was correct for the first term
but not quite right for the second?

John tells me that there are serine proteases with completely different
folds but with very similar active site geometry but that this is
considered to have occured due to convergent rather than divergent



Will Pitt Tel: 44-171-5806851
Crystallography Department, Fax: 44-171-5806803
Birkbeck College,
Malet Street,

On Fri, 24 May 1996, Sophia Kossida wrote:

> Dear Will,
> Two genes are said to be paralogous if they are derived from a duplication
> event, but orthologous if they are derived from a speciation event. This is
> how the above terms are used, at least, in an evolutionary context.
> Cheers
> Sophia
> =====================================================
> Sophia Kossida
> Merton College
> Oxford OX1 4JD
> England
> e-mail:
> tel : (44) (0) 1865 271263
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