title: Virtual Screening and Experimental Validation Identify Novel Inhibitors of the Plasmodium falciparum Atg8-Atg3 Protein-Protein Interaction.
abstract: New therapies are needed against malaria, a parasitic infection caused by Plasmodium falciparum, as drug resistance emerges against the current treatment, artemisinin. We previously characterized the Atg8-Atg3 protein-protein interaction (PPI), which is essential for autophagy and parasite survival. Herein we illustrate the use of virtual library screening to selectively block the PPI in the parasite without inhibiting the homologous interaction in humans by targeting the A-loop of PfAtg8. This A-loop is important for Atg3 binding in Plasmodium, but is absent from the human Atg8 homologues. In this proof-of-concept study, we demonstrate a shift in lipidation state of PfAtg8 and inhibition of P. falciparum growth in both blood- and liver-stage cultures upon drug treatment. Our results illustrate how in silico screening and structure-aided drug design against a PPI can be used to identify new hits for drug development. Additionally, as we targeted a region of Atg8 that is conserved within apicomplexans, we predict that our small molecule will have cross-reactivity against other disease-causing apicomplexans, such as Toxoplasma, Cryptosporidium, Theileria, Neospora, Eimeria, and Babesia.
authors.affiliation: Department of Biochemistry and Molecular Biology, Johns Hopkins School of Public Health and, Johns Hopkins Malaria Research Institute, 615 N. Wolfe Street, Baltimore, MD, 21205, USA.
authors.forename: Adelaide U P
authors.initials: AU
authors.lastname: Hain
authors.affiliation: Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD, 21205, USA.
authors.forename: Alexia S
authors.initials: AS
authors.lastname: Miller
authors.affiliation: The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD, 21205, USA.
authors.forename: Jelena
authors.initials: J
authors.lastname: Levitskaya
authors.affiliation: Department of Biochemistry and Molecular Biology, Johns Hopkins School of Public Health and, Johns Hopkins Malaria Research Institute, 615 N. Wolfe Street, Baltimore, MD, 21205, USA. jbosch@jhu.edu.
authors.forename: Jürgen
authors.identifier: http://orcid.org/0000-0002-2624-4105
authors.initials: J
authors.lastname: Bosch
mesh_terms: D000595:Amino Acid Sequence; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D015394:Molecular Structure; D021261:Parasitic Sensitivity Tests; D010963:Plasmodium falciparum / Q000737:chemistry / Q000187:drug effects* / Q000254:growth & development; D011485:Protein Binding / Q000187:drug effects; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D054852:Small Molecule Libraries / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D015800:Protozoan Proteins; D054852:Small Molecule Libraries
keywords: autophagy; drug design; malaria; protein-protein interactions; virtual screening