Haberland M E, Reynolds J A
J Biol Chem. 1975 Sep 10;250(17):6636-9.
The AI polypeptide chain from human high density serum lipoprotein has two accessible conformational states in aqueous solution. L-alpha-Palmitoyl lysophosphatidylcholine induces the transition between these two states at an equilibrium concentration of ligand of 2 X 10(-5)M, and the protein has a maximum binding capacity of 95 to 100 mol of lipid/mol of protein. The present study, together with previous investigations in this laboratory, suggests that the conformational state of AI in the presence of high levels of bound amphiphiles is similar to the in vivo state, and further, that this complex does not result from the insertion of AI into amphiphilic micelles. The mode of interaction of AI with amphiphilic ligands is shown to be significantly different from that of membrane proteins thus far investigated.
来自人高密度血清脂蛋白的AI多肽链在水溶液中有两种可及的构象状态。L-α-棕榈酰溶血磷脂酰胆碱在配体平衡浓度为2×10⁻⁵M时诱导这两种状态之间的转变，并且该蛋白质对脂质的最大结合能力为每摩尔蛋白质95至100摩尔脂质。本研究与本实验室先前的研究一起表明，在存在高水平结合两亲物的情况下，AI的构象状态类似于体内状态，并且进一步表明这种复合物不是由AI插入两亲性胶束中产生的。结果表明，AI与两亲性配体的相互作用模式与迄今为止研究的膜蛋白的相互作用模式有显著不同。
