Galactosaminogalactan

Galactosaminogalactan (GAG) is a polysaccharide that is found in the cell wall of certain fungi, including Aspergillus fumigatus. It plays a crucial role in the pathogenesis of invasive aspergillosis, a serious infection that can occur in people with weakened immune systems.

Structure

Galactosaminogalactan is composed of galactose and N-acetylgalactosamine residues. The exact structure can vary depending on the species of fungus, but in Aspergillus fumigatus, it is a linear heteropolysaccharide composed of α-1,4-linked galactose and α-1,4-linked N-acetylgalactosamine.

Function

In Aspergillus fumigatus, galactosaminogalactan serves several functions. It contributes to the structural integrity of the cell wall and is involved in adhesion to host tissues, which is a critical step in the establishment of infection. It also has immunomodulatory properties, suppressing the host immune response and promoting fungal survival.

Clinical significance

Galactosaminogalactan is a potential target for new antifungal therapies. Inhibiting its synthesis could weaken the fungal cell wall and make it more susceptible to the host immune response. It could also prevent the fungus from adhering to host tissues and suppress its immunomodulatory effects.

See also

• Aspergillus fumigatus
• Invasive aspergillosis
• Polysaccharide
• Cell wall
• Pathogenesis