Channel-like crystal structure of cinchoninium L-O-phosphoserine salt dihydrate.

Studies on the interactions between L-O- phosphoserine, as one of the simplest fragments of membrane components, and the Cinchona alkaloid cinchonine, in the crystalline state were performed. Cinchoninium L-O-phosposerine salt dihydrate (PhSerCin) crystallizes in a monoclinic crystal system, space group P2(1), with unit cell parameters: a = 8.45400(10) A, b = 7.17100(10) A, c = 20.7760(4) A, alpha = 90 degrees , beta = 98.7830(10) degrees , gamma = 90 degrees , Z = 2. The asymmetric unit consists of the cinchoninium cation linked by hydrogen bonds to a phosphoserine anion and two water molecules. Intermolecular hydrogen bonds connecting phosphoserine anions via water molecules form chains extended along the b axis. Two such chains symmetrically related by twofold screw axis create a "channel." On both sides of this channel cinchonine cations are attached by hydrogen bonds in which the atoms N1, O12, and water molecules participate. This arrangement mimics the system of bilayer biological membrane.