jm500390g_si_001.pdf (469.81 kB)
Ligand-Induced Conformational Change of Plasmodium falciparum AMA1 Detected Using 19F NMR
journal contribution
posted on 2014-08-14, 00:00 authored by Xiaopeng Ge, Christopher A. MacRaild, Shane M. Devine, Cael O. Debono, Geqing Wang, Peter
J. Scammells, Martin J. Scanlon, Robin F. Anders, Michael Foley, Raymond S. NortonWe
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.