{PDOC00563}
{PS00655; GLYCOSYL_HYDROL_F6_1}
{PS00656; GLYCOSYL_HYDROL_F6_2}
{BEGIN}
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* Glycosyl hydrolases family 6 signatures *
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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,E1].    The  enzymes  which are currently known to belong to this
family are listed below.

 - Agaricus bisporus exoglucanase 3 (cel3).
 - Cellulomonas fimi endoglucanase A (cenA).
 - Cellulomonas fimi exoglucanase A (cbhA).
 - 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-[GSAF]-x(2)-[GSA](2)-x-G
                    [D may be an 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: [LIVMYA]-[LIVA]-[LIVT]-[LIV]-E-P-D-[SAL]-[LI]-[PSAG]
                    [D is an active site residue]
-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:
           Henrissat B.; bernie@afmb.cnrs-mrs.fr

-Last update: May 2004 / Text revised.

[ 1] Beguin P.
     "Molecular biology of cellulose degradation."
     Annu. Rev. Microbiol. 44:219-248(1990).
     PubMed=2252383; DOI=10.1146/annurev.mi.44.100190.001251
[ 2] Gilkes N.R., Henrissat B., Kilburn D.G., Miller R.C. Jr., Warren R.A.J.
     "Domains in microbial beta-1, 4-glycanases: sequence conservation,
     function, and enzyme families."
     Microbiol. Rev. 55:303-315(1991).
     PubMed=1886523
[ 3] Henrissat B., Claeyssens M., Tomme P., Lemesle L., Mornon J.-P.
     "Cellulase families revealed by hydrophobic cluster analysis."
     Gene 81:83-95(1989).
     PubMed=2806912
[ 4] Henrissat B.
     "A classification of glycosyl hydrolases based on amino acid sequence
     similarities."
     Biochem. J. 280:309-316(1991).
     PubMed=1747104
[ 5] Rouvinen J., Bergfors T., Teeri T.T., Knowles J.K., Jones T.A.
     "Three-dimensional structure of cellobiohydrolase II from Trichoderma
     reesei."
     Science 249:380-386(1990).
     PubMed=2377893
[ 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.
     "Structural and functional relationships in two families of
     beta-1,4-glycanases."
     Eur. J. Biochem. 202:367-377(1991).
     PubMed=1761039
[E1] https://www.uniprot.org/docs/glycosid

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