Apolipoprotein domain interactions

H41. Huby, T., Doucet, C., Dieplinger, H., Chapman, J., and Thillet, J., Structural domains of apolipoprotein(a) and its interaction with apolipoprotein Bl00 in the lipoprotein(a) particle. Biochemistry 33, 3335-3341 (1994). 

About 5% of HDL and about 40 to 60% of VLDL protein are apolipoprotein C. ApoC-I is a 57-amino-acid residue polypeptide and is the smallest of the exchangeable apolipoproteins. CNBr treatment of apoC-I produced two fragments, apoC-I[l-38] and apoC-I[39-57] the amino-terminal fragment, apoC-I[l-38] had the stronger lipid affinity (Jackson et ai, 1974). In another study, the synthetic peptide apoC-I[32-57] was found to associate with phospholipid (Sparrow et al., 1977). Therefore, there appear to be at least two lipid-associating domains in apoC-I located between residues 1-31 and 32-57 (Fig. 7). The amphipathic helical domains of apoC-I are good examples of class A2 amphipathic helices. This supports experimental results showing that this protein interacts with lipid avidly. 

Saito, H., Lund-Katz, S., Phillips, M.C. 2004. Contributions of domain structure and lipid interaction to the functionality of exchangeable human apolipoproteins. Prog. Lipid Res. 43 350-380. 

Dong J, Peters-Libeu CA, Weisgraber KH, Segelke BW, Rupp B, Capila I, Hernaiz MJ, LeBrun LA, Linhardt RJ. Interaction of the N-terminal domain of apolipoprotein E4 with heparin. Biochemistry 2001 40 2826-2834. 

The cammon features of plasma lipoprotein structure are shown in Fig. 2. The interior of the lipoproteins contains the neutral lipids, cholesteryl ester and triglyceride. The exterior surface is a monomolecular film of specific proteins, termed apolipopro-teins, and the polar lipids, phosphatidylcholine and cholesterol. One possible arrangement (Edelstein et al., 1979) of the phosphatidylcholine, cholesterol and apolipoprotein A-1 (apoA-1) in HDL the most abundant of the plasma lipoproteins, is illustrated schematically in Fig. 3. In this model, there are no lipid domains in the surface of HDL. The phospholipid molecules are widely dispersed so that intermolecular associations can involve only apoprotein lipid and apoprotein apoprotein interactions. By contrast, with increasing size and a greater proportion of hydrophobic core volume, the structure of the larger lipoproteins more closely re-... 

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