The microbial degradation of cellulose and xylans requires several types of
enzymes such as endoglucanases (EC 18.104.22.168), cellobiohydrolases (EC 22.214.171.124)
(exoglucanases), or xylanases (EC 126.96.36.199) [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 G  or as the glycosyl hydrolases
family 11 [4,E1]. The enzymes which are currently known to belong to this
family are listed below.
Aspergillus awamori xylanase C (xynC).
Bacillus circulans, pumilus, stearothermophilus and subtilis xylanase
Clostridium acetobutylicum xylanase (xynB).
Clostridium stercorarium xylanase A (xynA).
Fibrobacter succinogenes xylanase C (xynC) which consist of two catalytic
domains that both belong to family 10.
Neocallimastix patriciarum xylanase A (xynA).
Ruminococcus flavefaciens bifunctional xylanase XYLA (xynA). This protein
consists of three domains: a N-terminal xylanase catalytic domain that
belongs to family 11 of glycosyl hydrolases; a central domain composed of
short repeats of Gln, Asn an Trp, and a C-terminal xylanase catalytic
domain that belongs to family 10 of glycosyl hydrolases.
Schizophyllum commune xylanase A.
Streptomyces lividans xylanases B (xlnB) and C (xlnC).
Trichoderma reesei xylanases I and II.
Two of the conserved regions in these enzymes are centered on glutamic acid
residues which have both been shown , in Bacillus pumilis xylanase, to be
necessary for catalytic activity. We have used both regions as signature
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