Re: "homology / similarity" of proteins

Kurt Giles (
Sun, 26 May 1996 09:54:50 +0200

On May 24, 8:57pm, Dr Alan Mills wrote:
> A third class of hydrolases which uses a similar His-Asp-Ser catalytic
> triad, but which, in general are not proteases, is the so-called
> alpha/beta hydrolase family, which are enzymes for a disparate set of
> small molecule reactions. The first structure to be elucidated in this
> class was that of acetylcholinesterase, by Joel Sussman's group in Israel
> before he took up his present post as Head of the PDB at BNL. Perhaps
> someone else can weigh in with the appropriate literature refs., and
> other members of this family.

Firstly, a very interesting point about the alpha/beta (a/b) hydrolase fold
proteins is that they have a His-ACID-Ser triad, where examples exist for both
Asp or Glu as the acid. The first member of this family to have it's structure
determined with the His-Glu-Ser triad was a lipase from the fungus Geotrichum
candidum (Schrag et al. 1991 Nature 351, 761-764) which came out a couple of
months before the acetylcholinesterase paper (Sussman et al. 1991 Science 253,
872-879). In the Schrag et al. paper it was mentioned that the structure bore a
similar topology to the previously determined structure of the N-terminal
domain of human pancreatic lipase. The paper describing the a/b hydrolase fold
is Ollis et al. 1992 Prot. Eng. 5, 197-211. This paper also discusses the
convergent/divergent evolution issue.

Information about a/b hydrolase fold proteins can be found on the ESTHER server


                              Dr. Kurt Giles                     
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