{PDOC00800}
{PS01042; HOMOSER_DHGENASE}
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* Homoserine dehydrogenase signature *
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Homoserine dehydrogenase  (EC  1.1.1.3)  (HDh)  [1,2]  catalyzes NAD-dependent
reduction of  aspartate  beta-semialdehyde into  homoserine.  This reaction is
the third step in a   pathway leading from aspartate to homoserine. The latter
participates in  the  biosynthesis of threonine and then isoleucine as well as
in that of methionine.

HDh is  found  either as a single chain protein as in some bacteria and yeast,
or as a bifunctional  enzyme consisting  of an N-terminal aspartokinase domain
and a  C-terminal  HDh  domain  as in bacteria such as Escherichia coli and in
plants.

As a signature pattern, we selected the best conserved region of Hdh.  This is
a segment  of  23  to  24  residues  located  in  the central section and that
contains two conserved aspartate residues.

-Consensus pattern: A-x(3)-G-[LIVMFY]-[STAG]-x(2,3)-[DNS]-P-x(2)-D-[LIVM]-x-G-
                    x-D-x(3)-K
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Last update: July 1998 / Pattern and text revised.

[ 1] Thomas D., Barbey R., Surdin-Kerjan Y.
     "Evolutionary relationships between yeast and bacterial homoserine
     dehydrogenases."
     FEBS Lett. 323:289-293(1993).
     PubMed=8500624
[ 2] Cami B., Clepet C., Patte J.-C.
     "Evolutionary comparisons of three enzymes of the threonine
     biosynthetic pathway among several microbial species."
     Biochimie 75:487-495(1993).
     PubMed=8395899

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