Beijing Duck Apolipoprotein Apoa-i Structure And Function

Apolipoprotein A- I (apoA- I ) is the main protein component of HDL and it plays a very important role in the metabolism of lipoprotein and antiatherosclorosis. During recent years, many meaningful advancements of the studies on structures and functional localization have been achieved. The characteristic of secondary structure of apolipoproteins is their amphiphatic α-helix (A H), which has a nonplar face of hydrophobic amino acids (AA) and a polar face with negatively charged AA at the center and the positively charged AA at the periphery. According to the "Snorkel Model// hypothesis of Segrest, et al., the structure of AH of apolipoproteins is suitable for it to bind to phospholipids, the hydrophobic AA residues of nonplar face can associate with the fatty acid chains, the charged residues of the polar face can form ion contact with the oppositely charged head group of the phospholipids. Segrest divided the AHs of apolipoproteins into 3 classes: class A (with 3 suclclass A₂, A, and A₄), class Y and class G*. Most AHs of apolipoprotein A-I are of class A.Beijng duck (BD) has been an ideal animal model for the study of metabolism and antiatherosclerosis. Keqin Wang, et al., discovered that BD has plcntiful plasma HDL and apoA- I with high LCAT activity and very low CETP activity. It proves to be unsusceptiblc to atherosclerosis even after a long term of feeding with high lipid food. Wang hypothesized that most of the cholesterol and cholesterol ester of BD is transported directly to liver mainly by HDL and in the end metabolized in liver through the pathway of HDL receptor.In order to elucidate the mechanism of the role of apoA- I in the metabolism of lipoprotein and cholesterol, we studied the...