Characterization of apolipoprotein B from human serum low density lipoprotein in n-dodecyl octaethyleneglycol monoether: an electron microscope study.

Abstract

The structure of the totally delipidated polypeptide (apolipoprotein B [apo B]) present in low-density serum lipoprotein [the main vehicle for plasma cholesterol transport] in detergent (n-dodecyl octaethyleneglycol monoether) solution was studied by EM. The protein-detergent complex appears as a rod-shaped particle, 75-80 nm long and 4.5-5.5 nm wide. The volume of this particle is consistent with the previously published composition reported by Watt and Reynolds (1980), of 2 copies of apo B and 5-6 equivalent micelles of detergent. The asymmetric particle possesses a high degree of flexibility and a strong tendency to self-associate in an orderly fashion. The extent of this association is pH dependent.