title: Ligand-induced conformational change of Plasmodium falciparum AMA1 detected using 19F NMR.
abstract: We established an efficient means of probing ligand-induced conformational change in the malaria drug target AMA1 using 19F NMR. AMA1 was labeled with 5-fluorotryptophan (5F-Trp), and the resulting 5F-Trp resonances were assigned by mutagenesis of the native Trp residues. By introducing additional Trp residues at strategic sites within a ligand-responsive loop, we detected distinct conformational consequences when various peptide and small-molecule ligands bound AMA1. Our results demonstrate an increase in flexibility in this loop caused by the native ligand, as inferred from, but not directly observed in, crystal structures. In addition, we found evidence for long-range allosteric changes in AMA1 that are not observed crystallographically. This method will be valuable in ongoing efforts to identify and characterize therapeutically relevant inhibitors of protein-protein interactions involving AMA1 and is generalizable to the study of ligand-induced conformational change in a wide range of other drug targets.
authors: Department of Biochemistry, La Trobe University , Melbourne 3086, Victoria, Australia.
authors: Xiaopeng
authors: X
authors: Ge
authors: Christopher A
authors: CA
authors: MacRaild
authors: Shane M
authors: SM
authors: Devine
authors: Cael O
authors: CO
authors: Debono
authors: Geqing
authors: G
authors: Wang
authors: Peter J
authors: PJ
authors: Scammells
authors: Martin J
authors: MJ
authors: Scanlon
authors: Robin F
authors: RF
authors: Anders
authors: Michael
authors: M
authors: Foley
authors: Raymond S
authors: RS
authors: Norton
mesh_terms: D000953:Antigens, Protozoan / Q000737:chemistry* / Q000235:genetics; D000962:Antimalarials / Q000737:chemistry; D005462:Fluorine Radioisotopes; D008024:Ligands; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D010963:Plasmodium falciparum / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D015800:Protozoan Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D000953:Antigens, Protozoan; D000962:Antimalarials; D005462:Fluorine Radioisotopes; D008024:Ligands; D008565:Membrane Proteins; D015800:Protozoan Proteins; D011994:Recombinant Proteins; C090077:apical membrane antigen I, Plasmodium