CHARACTERIZATION OF THE PRODUCTS OF THE HEME DETOXIFICATION PATHWAY IN MALARIAL LATE TROPHOZOITES BY X-RAY-DIFFRACTION

In a process inhibited by the quinoline antimalarial drugs, Plasmodia detoxify heme released during the degradation of hemoglobin by aggrega ting it into malarial pigment, an insoluble crystalline heme coordinat ion polymer. Synchrotron x-ray powder diffraction patterns for intact desiccated malarial trophozoites and synthetic beta-hematin have been measured; both materials correspond to a single crystalline triclinic lattice with unit cell parameters a = 12.2176(4), b = 14.7184(5), c = 8.0456(3) Angstrom; alpha = 90.200(2), beta = 96.806(3), gamma = 97.81 8(3) degrees and Z = 2. These results unambiguously demonstrate that h emozoin crystallites are identical to synthetic beta-hematin.