PROSITE documentation PDOC52008
Glycosyl hydrolases family 81 (GH81) domain profile


Glycoside hydrolases (GHs, EC 3.2.1.-) form a widespread group of enzymes that hydrolyze the glycoside bond between monosaccharide units or between a carbohydrate and an aglycone moiety. GHs can act specifically as exo-cleaving enzymes to remove the sugar units from the ends of chains and release small sugar products, or endo-cleaving enzymes to act within the polysaccharide chain and produce oligosaccharides. The GH family 81 (GH81) includes proteins with endo-β-1,3-glucanase widely distributed in plants, fungi, bacteria, archaea and viruses. GH81 proteins show rather diverse physiological roles. These proteins share a common region of around 650 amino acids that is characteristic of the family [1,2,3,4].

The core catalytic domain of family 81 GHs consists of an N-terminal β-sandwich subdomain, a C-terminal (α/β)6 barrel subdomain and an additional α/β-subdomain between them (see <PDB:4K3A>). The β-sandwich subdomain compacts with (α/β)6 barrel subdomain and forms a long binding cleft. Along the catalytic cleft there are a number of aromatic residues that are conserved in GH family 81 glucanases and may be involved in stacking interactions with the rings of the glucosyl residues of the substrate. Three amino acid residues that are conserved in the family have been proposed as candidate catalytic residues: an aspartate (acid catalyst) and two glutamates (proton donor and basic catalyst respectively). These residues are located in the base of the catalytic cleft present near the center of the (α/β)6 barrel [2,3,4].

Some proteins known to contain a GH81 domain are listed below:

  • Schizosaccharomyces pombe β-1,3-Endoglucanase (SpEng1), an extracellular protein that plays a critical role in cell cycle by helping in the dissolution of the septum.
  • Schizosaccharomyces pombe β-1,3-endoglucanase (SpEng2), an intracellular cytoplasmic protein involved in actin assembly.
  • Saccharomyces cerevisiae ScEng1, an extracellular protein that acts together with the Cts1 chitinase during cell separation to hydrolyze the cell wall components of the septum.
  • Saccharomyces cerevisiae ScEng2, an intracellular cytoplasmic protein.
  • Candida albicans β-1,3-endoglucanase (CAENG1), involved in cell wall separation.
  • Pneumocystis sp. β-1,3-endoglucanase, regulates cell-wall β-glucan processing during its life cycle.
  • Rhizomucor miehei RmLam81A.
  • Plant β-glucan-elicitor-binding-proteins (GBPs) that are usually found in the plasma membrane and are pasrt of a defense mechanism against fungal infection.
  • Paenibacillus sp. β-1,3-glucanas LamA.
  • Clostridium thermocellum Eng1 (CtLam81A), a β-1,3-glucanase belonging to cellulosomal complex.

The profile we developed covers the whole GH81 domain.

Last update:

October 2022 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

GH81, PS52008; Glycosyl hydrolases family 81 (GH81) domain profile  (MATRIX)


1AuthorsMartin-Cuadrado A.-B. Fontaine T. Esteban P.-F. del Dedo J.E. de Medina-Redondo M. del Rey F. Latge J.P. Vazquez de Aldana C.R.
TitleCharacterization of the endo-beta-1,3-glucanase activity of S. cerevisiae Eng2 and other members of the GH81 family.
SourceFungal. Genet. Biol. 45:542-553(2008).
PubMed ID17933563

2AuthorsZhou P. Chen Z. Yan Q. Yang S. Hilgenfeld R. Jiang Z.
TitleThe structure of a glycoside hydrolase family 81 endo-beta-1,3-glucanase.
SourceActa Crystallogr. D. Biol. Crystallogr. 69:2027-2038(2013).
PubMed ID24100321

3AuthorsPluvinage B. Fillo A. Massel P. Boraston A.B.
TitleStructural Analysis of a Family 81 Glycoside Hydrolase Implicates Its Recognition of beta-1,3-Glucan Quaternary Structure.
SourceStructure 25:1348-1359.e3(2017).
PubMed ID28781080

4AuthorsKumar K. Correia M.A.S. Pires V.M.R. Dhillon A. Sharma K. Rajulapati V. Fontes C.M.G.A. Carvalho A.L. Goyal A.
TitleNovel insights into the degradation of beta-1,3-glucans by the cellulosome of Clostridium thermocellum revealed by structure and function studies of a family 81 glycoside hydrolase.
SourceInt. J. Biol. Macromol. 117:890-901(2018).
PubMed ID29870811


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