Crystallization and preliminary X-ray analysis of the antimalarial and cytotoxic alkaloid cryptolepine complexed with the DNA fragment d(CCTAGG)2.

Crystals of the indoloquinoline alkaloid cryptolepine complexed with the DNA fragment d(CCTAGG)(2) have been grown by the hanging-drop technique at 293 K using ammonium sulfate as the precipitating agent. Over a period of three weeks, yellow tapering bullet-shaped crystals grew to maximum dimensions of 0.2 x 0.1 x 0.1 mm. The crystals belong to space group P6(4), with unit-cell parameters a = b = 29.960, c = 39.64 A, alpha = beta = 90, gamma = 120 degrees, and diffract to 1.4 A.