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- *******************************************
- * Glycosyl hydrolases family 6 signatures *
- *******************************************
-
- The microbial degradation of cellulose and xylans requires several types of
- enzymes such as endoglucanases (EC 3.2.1.4), cellobiohydrolases (EC 3.2.1.91)
- (exoglucanases), or xylanases (EC 3.2.1.8) [1,2]. Fungi and bacteria produces
- a spectrum of cellulolytic enzymes (cellulases) and xylanases which, on the
- basis of sequence similarities, can be classified into families. One of these
- families is known as the cellulase family B [3] or as the glycosyl hydrolases
- family 6 [4]. The enzymes which are currently known to belong to this family
- are listed below.
-
- - Cellulomonas fimi endoglucanase A (cenA).
- - Microspora bispora endoglucanase A (celA).
- - Streptomyces halstedii endoglucanases A (celA1).
- - Streptomyces strain KSM-9 endoglucanase 1 (casA).
- - Thermomonospora fusca endoglucanase E-2 (celB).
- - Trichoderma reesei exoglucanase II (CBH2).
-
- One of the conserved regions in these enzymes contains a conserved aspartic
- acid residue which is potentially involved [5] in the catalytic mechanism;
- the aspartate is followed by a cysteine which is involved in a disulfide bond
- [6]. A second conserved region contains an aspartate which seems [5] to be the
- proton donor in the catalytic mechanism. We have used both regions as
- signature patterns.
-
- -Consensus pattern: V-x-Y-x(2)-P-x-R-D-C-[GSA]-x(2)-[GSA](2)-x-G
- [D is a putative active site residue]
- [C is involved in a disulfide bond]
- -Sequences known to belong to this class detected by the pattern: ALL, except
- for celA1.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Consensus pattern: [LIVMFY]-[LIV](3)-E-P-D-x-[LIV]
- [D is the active site residue]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: 3.
-
- -Expert(s) to contact by email: Beguin P.
- phycel@pasteur.bitnet
- Henrissat B.
- bernie@cermav.grenet.fr
-
- -Last update: June 1994 / Text revised.
-
- [ 1] Beguin P.
- Annu. Rev. Microbiol. 44:219-248(1990).
- [ 2] Gilkes N.R., Henrissat B., Kilburn D.G., Miller R.C. Jr., Warren R.A.J.
- Microbiol. Rev. 55:303-315(1991).
- [ 3] Henrissat B., Claeyssens M., Tomme P., Lemesle L., Mornon J.P.
- Gene 81:83-95(1991).
- [ 4] Henrissat B.
- Biochem. J. 280:309-316(1991).
- [ 5] Rouvinen J., Bergfors T., Teeri T.T., Knowles J.K.C., Jones T.A.
- Science 249:380-386(1990).
- [ 6] Gilkes N.R., Claeyssens M., Aebersold R., Henrissat B., Meinke A.,
- Morrison H.D., Kilburn D.G., Warren R.A.J., Miller R.C. Jr.
- Eur. J. Biochem. 202:367-377(1991).
-