glycoside hydrolase family 64: laminaripentaose-producing, beta-1,3-glucanase (LPHase)-like
This subfamily is represented by the laminaripentaose-producing, beta-1,3-glucanase (LPHase) of Streptomyces matensis and related bacterial and ascomycete proteins. LPHase is a member of glycoside hydrolase family 64 (GH64), it is an inverting enzyme involved in the cleavage of long-chain polysaccharide beta-1,3-glucans, into specific pentasaccharide oligomers. LPHase is a two-domain crescent fold structure: one domain is composed of 10 beta-strands, eight coming from the N-terminus of the protein and two from the C-terminal region, and the protein has a second inserted domain; this cd includes both domains. This protein has an electronegative, substrate-binding cleft, and conserved Glu and Asp residues involved in the cleavage of the beta-1,3-glucan, laminarin, a plant and fungal cell wall component. Among bacteria, many beta-1,3-glucanases are implicated in fungal cell wall degradation. Also included in this family is GluB , the beta-1,3-glucanase B from Lysobacter enzymogenes Strain N4-7. Recombinant GluB demonstrated higher relative activity toward the branched-chain beta-1,3 glucan substrate zymosan A than toward linear beta-1,3 glucan substrates. Sometimes these two domains are found associated with other domains such as in the Catenulispora acidiphila DSM 44928 carbohydrate binding family 6 protein in which they are positioned N-terminal of a carbohydrate binding module, family 6 (CBM_6) domain. In the Cellulosimicrobium cellulans, glucan endo-1,3-beta-glucosidase, they are positioned N-terminal of a RICIN, carbohydrate-binding domain.
Structure:3GD9; Streptomyces matensis, laminaripentaose-producing, beta-1,3-glucanase in complex with laminaritetraose
Comment:The most prominent structural feature of the crescent-like LPHase is a wide groove with a predominantly electronegative charge running between the two domains.
Jiyao W et al.(2023). "The conserved domain database in 2023.",