Abnormal interaction of the human apolipoprotein A-I variant [Lys_107→0] with high density lipoproteins

Several isoforms of apoprotein A-I [apoA-I], the major apoprotein of high density lipoproteins [HDL], have been described. We compared the in vivo and in vitro properties of normal human apoA-I with those of apoA-I [Lys_107→0]. Fluorescence and circular dichroic spectra showed that deletion of Lys₁₀₇ decreases apoprotein self-association. In vivo metabolic studies in the rat indicated that the interaction of apoA-I [Lys_107→0] with HDL was lower than normal. We conclude that deletion of Lys₁₀₇ results in a reorganization of the apoprotein structure that decreases its potential to form hydrophobic associations.