{PDOC00794}
{PS01034; GH16_1}
{PS51762; GH16_2}
{BEGIN}
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* Glycosyl hydrolases family 16 (GH16) signature and domain profile *
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The glycosyl hydrolases family 16 (GH16) [1,E1] contains functionally
heterogeneous members, including beta-agarases, endo-1,3-beta-glucanases
(laminarinases), endo-beta-1,3-1,4-glucanases (lichenases), kappa-
carrageenases, endo-beta-galactosidases and xyloglucan endotransferases. These
enzymes share a common ancestor and have diverged significantly in their
primary sequence.
The GH16 catalytic domain has a classical sandwich-like beta-jelly roll fold,
formed by two main, closely packed and curved antiparallel beta sheets,
creating a deep channel harboring the catalytic machinery (see <PDB:1DYP>).
Even though the GH16 domains have now diverged significantly in their primary
sequences, they all feature a common catalytic motif, E-[ILV]-D-[IVAF]-
[VILMF](0,1)-E. The two glutamic acid residues in the conserved motif are the
nucleophile and the general base involved in catalysis, whereas the aspartic
acid residue is important in maintaining the relative position of these
catalytic amino acids [2,3].
Some proteins known to contain a GH16 domain are listed below:
- Bacterial beta-1,3-1,4-glucanases, or lichenases, (EC 3.2.1.73) mainly from
Bacillus but also from Clostridium thermocellum (gene licB), Fibrobacter
succinogenes and Rhodothermus marinus (gene bglA).
- Bacillus circulans beta-1,3-glucanase A1 (EC 3.2.1.39) (gene glcA).
- Alteromonas carrageenovora kappa-carrageenase (EC 3.2.1.83) (gene cgkA).
- Rhizobium meliloti endo-1,3-1,4-beta-glycanase exoK.
- Streptomyces coelicolor agarase (EC 3.2.1.81) (gene dagA).
- Zobellia galactanivorans beta-agarase A (EC 3.2.1.81) (gene agaA).
- Zobellia galactanivorans beta-agarase B (EC 3.2.1.81) (gene agaB).
- Saccharophagus sp. AG21 beta-agarase (gene agy1), includes a GH16 domain
and two CBM6 (carbohydrate binding type-6) domain (see <PDOC51175>).
- Microbulbifer thermotolerans agarase (agaA).
- Thermotoga maritima laminarinase.
- Saccharomyces cerevisiae beta-glucan synthesis-associated protein SKN1 [5].
- Saccharomyces cerevisiae beta-glucan synthesis-associated protein KRE6 [5].
Two closely clustered conserved glutamates have been shown [6] to be involved
in the catalytic activity of Bacillus licheniformis lichenase. We used the
region that contains these residues as a signature pattern. We have also
developed a profile that covers the entire GH16 domain.
-Consensus pattern: E-[LIV]-D-[LIVF]-x(0,1)-E-x(2)-[GQ]-[KRNF]-x-[PSTA]
[The 2 E's are active site residues]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: 4.
-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] Henrissat B.
"A classification of glycosyl hydrolases based on amino acid sequence
similarities."
Biochem. J. 280:309-316(1991).
PubMed=1747104
[ 2] Allouch J., Jam M., Helbert W., Barbeyron T., Kloareg B.,
Henrissat B., Czjzek M.
"The three-dimensional structures of two beta-agarases."
J. Biol. Chem. 278:47171-47180(2003).
PubMed=12970344; DOI=10.1074/jbc.M308313200
[ 3] Michel G., Chantalat L., Duee E., Barbeyron T., Henrissat B.,
Kloareg B., Dideberg O.
"The kappa-carrageenase of P. carrageenovora features a tunnel-shaped
active site: a novel insight in the evolution of Clan-B glycoside
hydrolases."
Structure 9:513-525(2001).
PubMed=11435116
[ 4] Thevissen K., Idkowiak-Baldys J., Im Y.-J., Takemoto J.,
Francois I.E.J.A., Ferket K.K.A., Aerts A.M., Meert E.M.K.,
Winderickx J., Roosen J., Cammue B.P.A.
"SKN1, a novel plant defensin-sensitivity gene in Saccharomyces
cerevisiae, is implicated in sphingolipid biosynthesis."
FEBS Lett. 579:1973-1977(2005).
PubMed=15792805; DOI=10.1016/j.febslet.2005.02.043
[ 5] Montijn R.C., Vink E., Mueller W.H., Verkleij A.J., Van Den Ende H.,
Henrissat B., Klis F.M.
"Localization of synthesis of beta1,6-glucan in Saccharomyces
cerevisiae."
J. Bacteriol. 181:7414-7420(1999).
PubMed=10601196
[ 6] Juncosa M., Pons J., Dot T., Querol E., Planas A.
"Identification of active site carboxylic residues in Bacillus
licheniformis 1,3-1,4-beta-D-glucan 4-glucanohydrolase by
site-directed mutagenesis."
J. Biol. Chem. 269:14530-14535(1994).
PubMed=8182059
[E1] http://www.cazy.org/GH16.html
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