Using Mutagenesis and Structural Biology to Map the Binding Site for the Plasmodium falciparum Merozoite Protein PfRh4 on the Human Immune Adherence Receptor

• DOI: 10.1074/jbc.m113.520346
• Publication Date: 2013-11-09T06:42:15Z
• Authors: Hyon Ju Park; Mara Guariento; Mateusz Maciejewski; Richard Hauhart; Wai-Hong Tham; Alan F. Cowman; Christoph Q. Schmidt; Haydyn D.T. Mertens; M. Kathryn Liszewski; Dennis E. Hourcade; Paul N. Barlow; John P. Atkinson
• Keywords: A-site; C3-convertase; Immunoprecipitation; Complement control protein

To survive and replicate within the human host, malaria parasites must invade erythrocytes. Invasion can be mediated by P. falciparum reticulocyte-binding homologue protein 4 (PfRh4) on merozoite surface interacting with complement receptor type 1 (CR1, CD35) erythrocyte membrane. The PfRh4 attachment site lies three N-terminal control modules (CCPs 1-3) of CR1, which intriguingly also accommodate binding regulatory sites for key activation-specific proteolytic products, C3b C4b. One these activities is decay-accelerating activity. Although does not impact C3b/C4b binding, it inhibit this convertase disassociating capability. Here, we have employed ELISA, co-immunoprecipitation, plasmon resonance to demonstrate that CCP contains all critical residues interaction. We fine mapped homologous substitution mutagenesis PfRh4-binding visualized a solution structure CCPs 1-3 derived NMR small angle x-ray scattering. cross-validated results creating an artificial through putative PfRh4-interacting from into their positions 8; strikingly, engineered had ∼30-fold higher affinity than native one in 1. These experiments define candidate CR1 merozoites gain access erythrocytes non-sialic acid-dependent pathway invasion.