title: The structure of human-plasma low-density lipoprotein B. An X-ray small-angle scattering study.
abstract: 1. X-ray small-angle scattering of human plasma lipoprotein B of the low-density fraction (rho = 1.016--1.060 g.cm-3) has been recorded to high precision at different electron density contrasts. 2. The overall structure of the particles is characterized by a quasi-spherical shape and radial symmetry. A maximum diameter of 23 nm and a molecular weight of 2.4 X 10(6) have been determined. 3. The internal structure is described in terms of a model consisting of spherical layers with different electron densities indicating that the neutral lipids are arranged in the core of the molecule up to a radius of about 8 nm surrounded by a monolayer of free cholesterol, phospholipids and protein. The neural lipids are shown to be in an ordered, liquid crystalline state at 4 degrees C and to undergo a thermotropic transition into a disordered state at higher temperatures.
mesh_terms: D002784:Cholesterol / Q000032:analysis; D005583:Fourier Analysis; D006801:Humans; D008077:Lipoproteins, LDL / Q000097:blood; D008433:Mathematics; D008970:Molecular Weight; D010743:Phospholipids / Q000032:analysis; D011487:Protein Conformation; D014280:Triglycerides / Q000032:analysis; D014961:X-Ray Diffraction
chemical_list: D008077:Lipoproteins, LDL; D010743:Phospholipids; D014280:Triglycerides; D002784:Cholesterol