Das S, Lengweiler U D, Seebach D, Reusch R N
Department of Microbiology, Michigan State University, East Lansing, MI 48824, USA.
Proc Natl Acad Sci U S A. 1997 Aug 19;94(17):9075-9. doi: 10.1073/pnas.94.17.9075.
Traditionally, the structure and properties of natural products have been determined by total synthesis and comparison with authentic samples. We have now applied this procedure to the first nonproteinaceous ion channel, isolated from bacterial plasma membranes, and consisting of a complex of poly(3-hydroxybutyrate) and calcium polyphosphate. To this end, we have now synthesized the 128-mer of hydroxybutanoic acid and prepared a complex with inorganic calcium polyphosphate (average 65-mer), which was incorporated into a planar lipid bilayer of synthetic phospholipids. We herewith present data that demonstrate unambiguously that the completely synthetic complex forms channels that are indistinguishable in their voltage-dependent conductance, in their selectivity for divalent cations, and in their blocking behavior (by La3+) from channels isolated from Escherichia coli. The implications of our finding for prebiotic chemistry, biochemistry, and biology are discussed.
传统上，天然产物的结构和性质是通过全合成并与真实样品进行比较来确定的。我们现已将此方法应用于首个从细菌质膜分离出的非蛋白质离子通道，该通道由聚（3-羟基丁酸酯）和多聚磷酸钙复合物组成。为此，我们现已合成了128聚体的羟基丁酸，并制备了与无机多聚磷酸钙（平均65聚体）的复合物，将其整合到合成磷脂的平面脂质双分子层中。我们在此展示的数据明确表明，完全合成的复合物形成的通道在电压依赖性电导、对二价阳离子的选择性以及阻断行为（被La3+）方面与从大肠杆菌分离出的通道没有区别。我们讨论了这一发现对生命起源前化学、生物化学和生物学的意义。
