Hypothetical epitope surface of pLDH. Structures of Pf-LDH and Pv-LDH or predicted structures of Po-LDH and Pm-LDH determined by molecular threading are shown in a computed chimeric pLDH tetramer where each of the 4 subunits is taken from the four human malarias. Pf-LDH, red; Pv-LDH, green; Pm-LDH, cyan, Po-LDH, yellow. A. Shows ribbon structure of the pLDH tetramer. B. Shows the molecular surface of the pLDH tetramer with surface-exposed residues unique to the different pLDH isoforms respectively indicated in black. C. Shows the molecular surface and residues shared between Po-, Pm-, Pv-LDH but that are different from Pf-LDH are indicated in black. The indicated residues are candidates for the epitopes of 9C1 and 20G1 antibody. D. Shows the pLDH tetramer with the heavy (red) and light (purple) chains of a typical antibody FAB fragment. This is to show the relative scale of the molecules to demonstrate that an epitope could conceivably span patches found in two different pLDH subunits.