title: Solution NMR characterization of apical membrane antigen 1 and small molecule interactions as a basis for designing new antimalarials.
abstract: Plasmodium falciparum apical membrane antigen 1 (PfAMA1) plays an important role in the invasion by merozoites of human red blood cells during a malaria infection. A key region of PfAMA1 is a conserved hydrophobic cleft formed by 12 hydrophobic residues. As anti-apical membrane antigen 1 antibodies and other inhibitory molecules that target this hydrophobic cleft are able to block the invasion process, PfAMA1 is an attractive target for the development of strain-transcending antimalarial agents. As solution nuclear magnetic resonance spectroscopy is a valuable technique for the rapid characterization of protein-ligand interactions, we have determined the sequence-specific backbone assignments for PfAMA1 from two P. falciparum strains, FVO and 3D7. Both selective labelling and unlabelling strategies were used to complement triple-resonance experiments in order to facilitate the assignment process. We have then used these assignments for mapping the binding sites for small molecules, including benzimidazoles, pyrazoles and 2-aminothiazoles, which were selected on the basis of their affinities measured from surface plasmon resonance binding experiments. Among the compounds tested, benzimidazoles showed binding to a similar region on both FVO and 3D7 PfAMA1, suggesting that these compounds are promising scaffolds for the development of novel PfAMA1 inhibitors. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: Bankala
authors.initials: B
authors.lastname: Krishnarjuna
authors.affiliation: Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: San Sui
authors.initials: SS
authors.lastname: Lim
authors.affiliation: Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: Shane M
authors.initials: SM
authors.lastname: Devine
authors.affiliation: Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: Cael O
authors.initials: CO
authors.lastname: Debono
authors.affiliation: Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: Raymond
authors.initials: R
authors.lastname: Lam
authors.affiliation: Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: Indu R
authors.initials: IR
authors.lastname: Chandrashekaran
authors.affiliation: NMR Research Centre, Indian Institute of Science, Bangalore, 560012, India.
authors.forename: Garima
authors.initials: G
authors.lastname: Jaipuria
authors.affiliation: Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Yagi
authors.affiliation: NMR Research Centre, Indian Institute of Science, Bangalore, 560012, India.
authors.forename: Hanudatta S
authors.initials: HS
authors.lastname: Atreya
authors.affiliation: Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Scanlon
authors.affiliation: Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: MacRaild
authors.affiliation: Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Scammells
authors.affiliation: Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria, 3052, Australia.
authors.forename: Raymond S
authors.initials: RS
authors.lastname: Norton
mesh_terms: D000595:Amino Acid Sequence; D000953:Antigens, Protozoan / Q000737:chemistry* / Q000378:metabolism*; D000962:Antimalarials / Q000737:chemistry / Q000378:metabolism*; D001562:Benzimidazoles / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D015195:Drug Design; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D010963:Plasmodium falciparum / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D015800:Protozoan Proteins / Q000737:chemistry* / Q000378:metabolism*; D011720:Pyrazoles / Q000737:chemistry / Q000378:metabolism; D054852:Small Molecule Libraries / Q000737:chemistry / Q000378:metabolism*; D013844:Thiazoles / Q000737:chemistry / Q000378:metabolism
chemical_list: D000953:Antigens, Protozoan; D000962:Antimalarials; D001562:Benzimidazoles; D008565:Membrane Proteins; D015800:Protozoan Proteins; D011720:Pyrazoles; D054852:Small Molecule Libraries; D013844:Thiazoles; C090077:apical membrane antigen I, Plasmodium; C031363:2-aminothiazoline
keywords: AMA1; NMR; SPR; fragments; isotopic labelling; resonance assignments