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Free keywords:
α-Galactosylceramide
C6-functionalized α-GalCer
monolayers
thermodynamics
structure
Abstract:
α-Galactosylceramide (KRN7000) is a ligand for the glycoprotein CD1d that presents lipid antigens to natural killer T cells. Therefore, KRN7000 as well as some modified version thereof have been widely investigated as part of novel immunotherapies. To examine the impact of structural modification, we investigated KRN7000 and C6-modified KRN7000 at the air-liquid interface using monolayer isotherms, BAM, IRRAS, GIXD and TRXF. The amino group has no influence on the highly ordered sub-gel structures found at lateral pressures relevant for biological membranes. Neither lateral compression nor the protonation state of the amino group has a measurable effect on the lattice structure, which is defined by strong and rigid intermolecular hydrogen-bonds. However, the first-order phase transition found for the C6-functionalized α-GalCer is connected with an extraordinary surface inhibited nucleation. Our study demonstrates that KRN7000 can be functionalized at C6 without significantly changing the structural properties.
