{PDOC00622}
{PS00776; GH11_1}
{PS00777; GH11_2}
{PS51761; GH11_3}
{BEGIN}
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* Glycosyl hydrolases family 11 (GH11) active sites signatures and domain profile *
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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 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
(xynA).
- 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.; bernie@afmb.cnrs-mrs.fr
-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).
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] 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).
PubMed=1359880
[ 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
[E1] https://www.uniprot.org/docs/glycosid
[E2] http://www.cazy.org/GH11.html
{END}
