Biophysical Evidence of Lipid and Carbohydrate Binding Activities of Shrimp High Density Lipoprotein / B Glucan Binding Protein

Crustacean High Density Lipoprotein / β-Glucan Binding Protein (HDL / BGBP) has been studied due to its role in nutrition and immune response via activation of the defense cells (hemocytes) upon binding 1,3-D-β-glucan carbohydrates. In this study, HDL / BGBP was found to be composed mainly of beta sheets, as determined by circular dichroism. Lipoprotein aggregation resulted when HDL / BGBP interacted with phospolipid vesicles, laminaribiose (1,3-β-glucan disaccharide) or heparin. HDL / BGBP has similar dissociation constants for laminaribiose (Kd=22 mM) or heparin (Kd=46 mM) as determined by 90° light scattering.