Laetiporus sulphureus lectin N-terminal ricin-B-like domain (LSL-N)

The N-terminal ricin-B domain of LSLa (Laetiporus sulphureus lectin) is a carbohydrate-binding module found in the hemolytic toxin produced by the mushroom Laetiporus sulphureus (Tateno & Goldstein, 2003). This domain adopts a beta-trefoil fold, characteristic of the ricin-B family, and is responsible for the specific recognition and binding of the toxin to cell surface glycoconjugates containing galactose or N-acetylgalactosamine (Mancheño et al., 2005). While the C-terminal domain of LSLa is responsible for membrane insertion and pore formation, the N-terminal domain is crucial for targeting the toxin to the host cell membrane (UniProt P83406). In a research context, this domain is studied for its potential in glycan profiling and as a delivery vehicle for targeting specific cell types, although it is not a conventional therapeutic target. Its primary biological role is as a component of a fungal defense or predatory toxin that induces hemolysis and cell death. There are currently no approved drugs targeting this domain, but small-molecule carbohydrates can act as competitive inhibitors of its binding activity in experimental settings. Structural studies have revealed that the domain forms a hexameric assembly in the context of the full toxin, which is essential for its pore-forming efficiency.

Other names

LSLa N-terminal domainLSL lectin domainRicin-B-like domain of Laetiporus sulphureus lectinLSLa-N

Competitive inhibition of carbohydrate binding by specific sugars such as lactose or N-acetylgalactosamine