Database: PROSITE(DOC)
Entry: PDOC00622
LinkDB: PDOC00622
Original site: PDOC00622 
{PS00776; GH11_1}
{PS00777; GH11_2}
{PS51761; GH11_3}
* Glycosyl hydrolases family 11 (GH11) active sites signatures and domain profile *

The microbial degradation  of cellulose and  xylans requires  several types of
enzymes such as endoglucanases (EC,  cellobiohydrolases (EC
(exoglucanases), or xylanases (EC [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 [3] or as  the glycosyl hydrolases
family 11  (GH11)  [4,E1,E2].  Family  11  is monospecific, only consisting of
xylanases. 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.

The GH11  domain  folds  into a jelly-roll shape likened to a partially closed
right hand  (see  <PDB:4HK8>).  Several anti-parallel beta-strands bend almost
90 to  produce  a  substrate-binding groove characteristic of the GH11 domain
active sites.  Two  catalytic Glu residues face each other from opposite sides
of the  groove.  The  hydrolysis  reaction  is  believed  to  follow a double-
displacement mechanism,  with  one  Glu  residue acting as a general acid/base
catalyst and the other as a nucleophile.

Two of the conserved regions in  these enzymes  are  centered on glutamic acid
residues which have both  been shown [5], in Bacillus pumilis xylanase,  to be
necessary  for  catalytic activity.  We  have  used  both regions as signature
patterns. We have also developed a profile that covers the entire GH11 domain.

-Consensus pattern: [PSA]-[LQ]-x-E-[YF]-Y-[LIVM](2)-[DE]-x-[FYWHN]
                    [E is an active site residue]
-Sequences known to belong to this class detected by the pattern: ALL,  except
 for Piromyces sp. xynA.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Consensus pattern: [LIVMF]-x(2)-E-[AG]-[YWG]-[QRFGS]-[SG]-[STAN]-G-x-[SAF]
                    [E is an active site residue]
-Sequences known to belong to this class detected by the pattern: ALL,  except
 for Piromyces sp. xynA.
-Other sequence(s) detected in Swiss-Prot: 3.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Expert(s) to contact by email:
           Henrissat B.;

-Last update: June 2015 / Text revised; profile added.

[ 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).
[ 3] Henrissat B., Claeyssens M., Tomme P., Lemesle L., Mornon J.-P.
     "Cellulase families revealed by hydrophobic cluster analysis."
     Gene 81:83-95(1989).
[ 4] Henrissat B.
     "A classification of glycosyl hydrolases based on amino acid sequence
     Biochem. J. 280:309-316(1991).
[ 5] Ko E.P., Akatsuka H., Moriyama H., Shinmyo A., Hata Y., Katsube Y.,
     Urabe I., Okada H.
     "Site-directed mutagenesis at aspartate and glutamate residues of
     xylanase from Bacillus pumilus."
     Biochem. J. 288:117-121(1992).
[ 6] Wan Q., Zhang Q., Hamilton-Brehm S., Weiss K., Mustyakimov M.,
     Coates L., Langan P., Graham D., Kovalevsky A.
     "X-ray crystallographic studies of family 11 xylanase Michaelis and
     product complexes: implications for the catalytic mechanism."
     Acta Crystallogr. D 70:11-23(2014).
     PubMed=24419374; DOI=10.1107/S1399004713023626
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