Plasma particles, interactions among

HDL particle. Apo A1 is a cofactor for LCAT (A. Jonas, 2000) and the conversion of cholesterol to CE (Section 2.2) induces the formation of a neutral lipid core and the concomitant change in particle shape. Triacylglycerol molecules are introduced into the core of spherical HDL as a consequence of CE transfer protein activity. The apo A1 amphipathic a-helices are embedded among the PL molecules on the surface of spherical HDL (Fig. 7) but the detailed conformations of the apo A1 molecules are not known. Spherical HDL in plasma can be remodeled via a fusion event into large and small particles by PL transfer protein (K.A. Rye, 2001). Some HDL particles contain both apo A1 and apo A2 molecules and the interactions between these two proteins need to be understood. The presence of apo A2 inhibits HDL remodeling by CE transfer protein and the dissociation of apo A1 molecules to create pre-p-HDL. It seems that apo A2 interacts with apo A1 and reduces the ability of the latter to desorb from the HDL particle surface (K.A. Rye, 2003). 

Foremost among these are the electric fields generated by the solar wind-geomagnetic field interaction, the presence of intense particle precipitation within the auroral oval, the polar wind escape of thermal plasma, and other features resulting fi om the auroral disturbance of the neutral atmosphere. 

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