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- *****************************************************
- * Kazal serine protease inhibitors family signature *
- *****************************************************
-
- The Kazal inhibitor family [1] is one of the numerous families of serine
- proteinase inhibitors. The basic structure of such a type of inhibitor is
- shown in the following schematic representation:
-
- +------------------+
- | |
- *******************|***
- xxxxxxxxCxxxxxxCx#xxxxxCxxxxxxxxxxCxxCxxxxxxxxxxxxxxxxxC
- | | | |
- | +-------------|-----------------+
- +----------------------------+
-
- 'C': conserved cysteine involved in a disulfide bond.
- '#': active site residue.
- '*': position of the pattern.
-
- The proteins known to belong to this family are:
-
- - Pancreatic secretory trypsin inhibitor (PSTI), whose physiological function
- is to prevent the trypsin-catalyzed premature activation of zymogens within
- the pancreas.
- - Mammalian seminal acrosin inhibitors.
- - Canidae and felidae submandibular gland double-headed protease inhibitors,
- which contain two Kazal-type domains, the first one inhibits trypsin and
- the second one elastase.
- - Avian ovomucoids, which consist of three Kazal-type domains.
- - Chicken ovoinhibitor [2], which consists of seven Kazal-type domains.
- - Bdellin B-3 [3], a leech trypsin inhibitor.
- - A mice prostatic secretory glycoprotein [4], induced by androgens, and
- which exhibits anti-trypsin activity.
- - An eel peptide, which is probably a pancreatic serine proteinase inhibitor
- [5].
- - An elastase inhibitor from a sea anemone [6].
- - Pig intestinal peptide PEC-60 [7]. This protein, while highly similar to
- other members of the Kazal family, does not seem to act as a protease
- inhibitor. Its exact biological function is not yet established, but it is
- known to inhibit the glucose-induced insulin secretion from perfused
- pancreas and to play a role in the immune system.
-
- The pattern we developed to pick up Kazal-type inhibitors spans a region
- beginning with the second cysteine and ending with the fifth one.
-
- -Consensus pattern: C-x(7)-C-x(6)-Y-x(3)-C-x(2,3)-C
- [The four C's are involved in disulfide bonds]
- -Sequences known to belong to this class detected by the pattern: ALL, except
- for the sea anemone inhibitor which has six residues between the last two Cys
- of the pattern.
- -Other sequence(s) detected in SWISS-PROT: yeast hypothetical protein YKL034w.
-
- -Note: there are two residues between the last two cysteines in the pattern in
- all sequences except for that of bdellin B-3.
- -Note: this pattern will fail to detect the first of the three Kazal domains
- in some of the ovomucoids.
-
- -Last update: June 1994 / Text revised.
-
- [ 1] Laskowski M., Kato I.
- Annu. Rev. Biochem. 49:593-626(1980).
- [ 2] Scott M.J., Huckaby C.S., Kato I., Kohr W.J., Laskowski M. Jr.,
- Tsai M.-J., O'Malley B.W.
- J. Biol. Chem. 262:5899-5907(1987).
- [ 3] Fink E., Rehm H., Gippner C., Bode W., Eulitz M., Machleidt W., Fritz H.
- Biol. Chem. Hoppe-Seyler 367:1235-1242(1986).
- [ 4] Mills J.S., Needham M., Parker M.G.
- EMBO J. 6:3711-3717(1987).
- [ 5] Conlon J.M., Thim L.
- Eur. J. Biochem. 174:149-153(1988).
- [ 6] Tschesche H., Kolkenbrock H., Bode W.
- Biol. Chem. Hoppe-Seyler 368:1297-1304(1987).
- [ 7] Liepinsh E., Berndt K.D., Sillard R., Mutt V., Otting G.
- J. Mol. Biol. 239:137-153(1994).
-