{PDOC00712}
{PS00920; NITRIL_CHT_1}
{PS00921; NITRIL_CHT_2}
{BEGIN}
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* Nitrilases / cyanide hydratase signatures *
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Nitrilases  (EC 3.5.5.1)   are   enzymes  that  convert  nitriles  into  their
corresponding acids and ammonia. They are widespread in microbes as well as in
plants where    they    convert indole-3-acetonitrile to the hormone indole-3-
acetic acid.  A  conserved   cysteine has been shown [1,2] to be essential for
enzyme activity;  it  seems  to  be  involved  in a nucleophilic attack on the
nitrile carbon atom.

Cyanide hydratase (EC  4.2.1.66) converts HCN to formamide. In phytopathogenic
fungi, it  is  used  to  avoid the toxic effect of cyanide released by wounded
plants [3].  The sequence of cyanide hydrolase is evolutionary related to that
of nitrilases.

Yeast hypothetical proteins YIL164c and YIL165c also belong to this family.

As signature  patterns for  these  enzymes, we selected two conserved regions.
The first  is  located  in  the  N-terminal  section  while  the second, which
contains the active site cysteine, is located in the central section.

-Consensus pattern: G-x(2)-[LIVMFY](2)-x-[IF]-x-E-x(2)-[LIVM]-x-G-Y-P
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Consensus pattern: G-[GAQ]-x(2)-C-[WA]-E-[NH]-x(2)-[PST]-[LIVMFYS]-x-[KR]
                    [C is the active site residue]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Last update: November 1995 / Patterns and text revised.

[ 1] Kobayashi M., Izui H., Nagasawa T., Yamada H.
     "Nitrilase in biosynthesis of the plant hormone indole-3-acetic acid
     from indole-3-acetonitrile: cloning of the Alcaligenes gene and
     site-directed mutagenesis of cysteine residues."
     Proc. Natl. Acad. Sci. U.S.A. 90:247-251(1993).
     PubMed=8419930
[ 2] Kobayashi M., Komeda H., Yanaka N., Nagasawa T., Yamada H.
     "Nitrilase from Rhodococcus rhodochrous J1. Sequencing and
     overexpression of the gene and identification of an essential cysteine
     residue."
     J. Biol. Chem. 267:20746-20751(1992).
     PubMed=1400390
[ 3] Wang P., VanEtten H.D.
     "Cloning and properties of a cyanide hydratase gene from the
     phytopathogenic fungus Gloeocercospora sorghi."
     Biochem. Biophys. Res. Commun. 187:1048-1054(1992).
     PubMed=1382413

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