The first coherent model of a spherical HDL particle, and of the organization of ApoA- I within it, was proposed by W. Sean Davidson and colleagues from the University of Cincinnati in 2008.[7] What these investigators did was take a mixture of HDL particles – some particles containing both apoA-I and apoA-II, others only apoA-I – so that they had a representative average of all of the HDL particles in the mixture. What they found was that the vast majority of the HDL particles appeared to contain 3 copies of apoA-I – in other words, an additional apoA-I had moved to combine with the original 2 apoA-I copies present in the discoidal HDL as it moved metabolically to become a sphere.
Looking carefully at the schematic in the Figure, it can be seen that the 3 copies of apoA-I (shown in white, red, and green) interact intimately to create the skeleton of a spheroidal HDL particle, and more recently, collaboration between Sean Davidson’s laboratory and our own has enabled us to progress further with our understanding of the basic organization of the apoA-I structural unit in HDL particles.
J Clin Lipidol. 2011; 5(6).[7]From the lab of W. Sean Davidson: Gangani RA, Silva D, Huang R, et al. Structure of apolipoprotein A-I in spherical high density lipoproteins of different sizes. PNAS 2008;105(34):12176-81.
