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* Ferritin iron-binding regions signatures *
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Ferritin [1,2] is one of the major non-heme iron storage proteins. It consists
of a mineral core of hydrated ferric  oxide, and a multi-subunit protein shell
which  englobes   the  former  and   assures   its   solubility in  an aqueous
environment.

In animals the protein is mainly cytoplasmic  and  there  are generally two or
more genes that encodes for closely related subunits (in mammals there are two
subunits which are known as H(eavy) and L(ight)).  In plants ferritin is found
in the chloroplast [3].

There are a number  of well conserved  region in the sequence of ferritins. We
have selected two  of  these regions to  develop signature patterns. The first
pattern is located in the  central  part  of  the  sequence of ferritin and it
contains  three  conserved  glutamate  which are thought to be involved in the
binding of iron.  The second pattern  is located in the C-terminal section, it
corresponds to a region  which forms a hydrophilic channel through which small
molecules and ions can gain access to the central cavity of the molecule; this
pattern also  includes  conserved  acidic  residues  which are potential metal
binding sites.

-Consensus pattern: E-x-[KR]-E-x(2)-E-[KR]-[LF]-[LIVMA]-x(2)-Q-N-x-R-x-G-R
                    [The 3 E's are potential iron ligands]
-Sequences known to belong to this class detected by the pattern: ALL,  except
 for ferritin 1 from Schistosoma mansoni
-Other sequence(s) detected in SWISS-PROT: NONE.

-Consensus pattern: D-x(2)-[LIVMF]-[STAC]-[DH]-F-[LI]-[EN]-x(2)-[FY]-L-x(6)-
                    [LIVM]-[KN]
                    [The second D and the E are potential iron ligands]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: NONE.

-Last update: October 1993 / Patterns and text revised.

[ 1] Crichton R.R., Charloteaux-Wauters M.
     Eur. J. Biochem. 164:485-506(1987).
[ 2] Theil E.C.
     Annu. Rev. Biochem. 56:289-315(1987).
[ 3] Ragland M., Briat J.-F., Gagnon J., Laulhere J.-P., Massenet O.,
     Theil E.C.
     J. Biol. Chem. 265:18339-18344(1990).