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* Histidine acid phosphatases signatures *
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Acid phosphatases (EC 3.1.3.2)  are  a  heterogeneous group  of  proteins that
hydrolyze phosphate esters, optimally at low pH.  It has been shown [1] that a
number of acid phosphatases, from both  prokaryotes and eukaryotes,  share two
regions of  sequence  similarity,  each  centered around a conserved histidine
residue. These  two  histidines  seem to be involved in the enzymes' catalytic
mechanism [2,3].  The first histidine is located in the N-terminal section and
forms a  phosphohistidine  intermediate  while the second is located in the C-
terminal section  and possibly acts as proton donor. Enzymes belonging to this
family are called 'histidine acid phosphatases' and are listed below:

 - Escherichia coli pH 2.5 acid phosphatase (gene appA).
 - Escherichia coli glucose-1-phosphatase (EC 3.1.3.10) (gene agp).
 - Yeast constitutive and repressible acid phosphatases (genes PHO3 and PHO5).
 - Fission yeast acid phosphatase (gene pho1).
 - Aspergillus phytases A and B (EC 3.1.3.8) (gene phyA and phyB).
 - Mammalian lysosomal acid phosphatase.
 - Mammalian prostatic acid phosphatase.

-Consensus pattern: [LIVM]-x(2)-[LIVMA]-x(2)-[LIVM]-x-R-H-[GN]-x-R-x-P
                    [H is the phosphohistidine residue]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: NONE.

-Consensus pattern: [LIVM]-x-[LIVMFA]-x(2)-[STAG]-H-D-[STAN]-x-[LIVM]-x(2)-
                    [LIVMFY]-x(2)-[STA]
                    [H is an active site residue]
-Sequences known to belong to this class detected by the pattern: ALL,  except
 for rat prostatic acid  phosphatase  which  seems to  have Tyr instead of the
 active site His
-Other sequence(s) detected in SWISS-PROT: human transducin beta chain 3.

-Last update: June 1994 / Patterns and text revised.

[ 1] van Etten R.L., Davidson R., Stevis P.E., MacArthur H., Moore D.L.
     J. Biol. Chem. 266:2313-2319(1991).
[ 2] Ostanin K., Harms E.H., Stevis P.E., Kuciel R., Zhou M.-M.,
     van Etten R.L.
     J. Biol. Chem. 267:22830-22836(1992).
[ 3] Schneider G., Lindqvist Y., Vihko P.
     EMBO J. 12:2609-2615(1993).