************************
* HIT family signature *
************************

Recently a family  of small proteins  of about 12 to 16 Kd  has been described
[1]. This family currently consists of:

 - Bovine protein kinase C inhibitor 1 (PKCI-1). PKCI-1 seems to be, in vitro,
   a specific inhibitor of PKC. It has been shown to bind zinc.
 - Yeast protein HIT1.
 - Escherichia coli hypothetical protein ycfF.
 - A hypothetical 13.2 Kd protein in hisE 3'region in Azospirillum brasilense.
 - A hypothetical 13.1 Kd protein in p37 5'region in Mycoplasma hyorhinis.
 - A hypothetical 12.4 Kd protein in psbAII  5'region  in Synechococcus strain
   PCC 7942.

The zinc-binding  site  of PKCI-1 [2]  consists  of  three histidines that are
closely positioned. These histidines are  perfectly  conserved  in all members
of this family for which  the name HIT, for HIstidine Triad, has been proposed
[1]. Except for PKCI-1, the function of these proteins is not yet known. Their
widespread evolutionary conservation suggests that they are important for some
cellular process(es).

As a signature pattern, we selected the region of the histidine triad.

-Consensus pattern: N-x(4)-[GA]-x-Q-x-[LIVM]-x-H-x-H-[LIVMF]-H
                    [The three H's are probaby zinc ligands]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in SWISS-PROT: NONE.

-Expert(s) to contact by email: Seraphin B.
                                seraphin@embl-heidelberg.de

-Last update: June 1994 / Text revised.

[ 1] Seraphin B.
     DNA Seq. 3:177-179(1992).
[ 2] Mozier N.M., Walsh M.P., Pearson J.D.
     FEBS Lett. 279:14-18(1991).