Glycoside Hydrolase Family 64

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• Author: ^^^Julie Grondin^^^
• Responsible Curator: ^^^Harry Brumer^^^

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Glycoside Hydrolase Family GH64
Clan	GH-x
Mechanism	inverting
Active site residues	known
CAZy DB link
http://www.cazy.org/GH64.html

Substrate specificities

All characterized members of the GH64 family are laminaripentaose-producing β-1,3-glucanases (EC 3.2.1.39] from the GH64-TLP (thaumatin-like protein) superfamily. They are found in bacteria and fungal species, and are particularly abundant in the genomes of various Streptomyces and Fusarium species.

Activity has been shown on insoluble and soluble β-1,3-glucans, including curdlan [1, 2, 3], colloidal pachyman [1, 3, 4], laminarin [1, 3, 4], and zymosan A [1, 2], a commercial preparation of partially-purified yeast cell walls (contains branched glucans).

Kinetics and Mechanism

GH64 enzymes follow an inverting mechanism, first shown by ¹H-NMR during the hydrolysis of laminarin [4], thus operating by a single-displacement mechanism.

Catalytic Residues

The general acid and base for this family were first proposed in 2009, based on the active site topology and residue orientation observed in the first published structure in this family [3], the LPHase from Streptoymces matensis. This group continued its characterization of this enzyme, and confirmed the identity of the general acid (Glu154) and general base (Asp170), via site-directed mutagenesis, chemical rescue, and kinetic analysis [5].

Three-dimensional structures

Content is to be added here.

Family Firsts

First stereochemistry determination

Laminaripentaose-producing β-1,3-glucanase (LPHase) from Streptomyces matensis DIC-108.[4]

First catalytic nucleophile identification

Laminaripentaose-producing β-1,3-glucanase (LPHase) from Streptomyces matensis DIC-108.[5]

First general acid/base residue identification

Laminaripentaose-producing β-1,3-glucanase (LPHase) from Streptomyces matensis DIC-108.[5]

First 3-D structure

Laminaripentaose-producing β-1,3-glucanase (LPHase) from Streptomyces matensis DIC-108.[3]

References

1. Nakabayashi, M. (1998) Structure of the gene encoding laminaripentaose-producing β-1,3-glucanase (LPHase) of Streptomyces matensis DIC-108. J. Ferment. Bioengineer. 85, 459-464. DOI=10.1016/s0922-338x(98)80062-7

2. Palumbo JD, Sullivan RF, and Kobayashi DY. (2003). Molecular characterization and expression in Escherichia coli of three beta-1,3-glucanase genes from Lysobacter enzymogenes strain N4-7. J Bacteriol. 2003;185(15):4362-70. DOI:10.1128/JB.185.15.4362-4370.2003 |
3. Wu HM, Liu SW, Hsu MT, Hung CL, Lai CC, Cheng WC, Wang HJ, Li YK, and Wang WC. (2009). Structure, mechanistic action, and essential residues of a GH-64 enzyme, laminaripentaose-producing beta-1,3-glucanase. J Biol Chem. 2009;284(39):26708-15. DOI:10.1074/jbc.M109.010983 |
4. Nishimura T, Bignon C, Allouch J, Czjzek M, Darbon H, Watanabe T, and Henrissat B. (2001). Streptomyces matensis laminaripentaose hydrolase is an 'inverting' beta-1,3-glucanase. FEBS Lett. 2001;499(1-2):187-90. DOI:10.1016/s0014-5793(01)02551-0 |
5. Shrestha KL, Liu SW, Huang CP, Wu HM, Wang WC, and Li YK. (2011). Characterization and identification of essential residues of the glycoside hydrolase family 64 laminaripentaose-producing-β-1, 3-glucanase. Protein Eng Des Sel. 2011;24(8):617-25. DOI:10.1093/protein/gzr031 |