{PDOC51405}
{PS51405; HEME_HALOPEROXIDASE}
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* Heme haloperoxidase family profile *
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Heme  haloperoxidase  or  chloroperoxidase  (CPO)  is  an  ~250  residue heme-
containing  glycoprotein  that  is  secreted  by  various fungi. CPO was first
identified   in   Caldariomyces   fumago   where  it  catalyzes  the  hydrogen
peroxide-dependent  chlorination  of cyclopentanedione during the biosynthesis
of  the  antibiotic caldarioymcin. Additionally, heme haloperoxidase catalyzes
the  iodination  and  bromination  of  a  wide  range  of  substrates. Besides
performing   H2O2-dependent   halogenation  reactions,  the  enzyme  catalyzes
dehydrogenation  reactions. CPO also functions as a catalase, facilitating the
decomposition  of  hydrogen  peroxide  to  oxygen and water. Furthermore, heme
haloperoxidase  catalyzes P450-like oxygen insertion reactions. The capability
of  heme haloperoxidase to perform these diverse reactions makes it one of the
most versatile of all known heme proteins [1,2].

Despite  functional  similarities with other heme enzymes, heme haloperoxidase
folds into a novel tertiary structure dominated by eight helical segments (see
<PDB:  1CPO>)  [3]. Structurally, heme haloperoxidase is unique, but it shares
features  with  both  peroxidases  and  P450  enzymes.  As  in cytochrome P450
enzymes,  the  proximal  heme ligand of the heme haloperoxidase is a cysteine,
but  similar  to  peroxidases,  the distal side of the heme is polar. However,
unlike  other  peroxidases,  the normally conserved distal arginine is lacking
and the catalytic acid base is a glutamic acid and not a histidine [4].

The  profile  we  developed  covers  the  whole  conserved  region of the heme
haloperoxidase family.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Last update: September 2008 / First entry.

[ 1] Hofrichter M., Ullrich R.
     "Heme-thiolate haloperoxidases: versatile biocatalysts with
     biotechnological and environmental significance."
     Appl. Microbiol. Biotechnol. 71:276-288(2006).
     PubMed=16628447; DOI=10.1007/s00253-006-0417-3
[ 2] Manoj K.M., Hager L.P.
     "Chloroperoxidase, a janus enzyme."
     Biochemistry 47:2997-3003(2008).
     PubMed=18220360; DOI=10.1021/bi7022656
[ 3] Sundaramoorthy M., Terner J., Poulos T.L.
     "The crystal structure of chloroperoxidase: a heme
     peroxidase--cytochrome P450 functional hybrid."
     Structure 3:1367-1377(1995).
     PubMed=8747463
[ 4] Kuhnel K., Blankenfeldt W., Terner J., Schlichting I.
     "Crystal structures of chloroperoxidase with its bound substrates and
     complexed with formate, acetate, and nitrate."
     J. Biol. Chem. 281:23990-23998(2006).
     PubMed=16790441; DOI=10.1074/jbc.M603166200

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