title: The effect of fusidic acid on Plasmodium falciparum elongation factor G (EF-G).
abstract: Inhibition of growth of the malaria parasite Plasmodium falciparum by known translation-inhibitory antibiotics has generated interest in understanding their action on the translation apparatus of the two genome containing organelles of the malaria parasite: the mitochondrion and the relic plastid (apicoplast). We report GTPase activity of recombinant EF-G proteins that are targeted to the organelles and further use these to test the effect of the EF-G inhibitor fusidic acid (FA) on the factor-ribosome interface. Our results monitoring locking of EF-G·GDP onto surrogate Escherichia coli ribosomes as well as multi-turnover GTP hydrolysis by the factor indicate that FA has a greater effect on apicoplast EF-G compared to the mitochondrial counterpart. Deletion of a three amino acid (GVG) sequence in the switch I loop that is conserved in proteins of the mitochondrial EF-G1 family and the Plasmodium mitochondrial factor, but is absent in apicoplast EF-G, demonstrated that this motif contributes to differential inhibition of the two EF-Gs by FA. Additionally, the drug thiostrepton, that is known to target the apicoplast and proteasome, enhanced retention of only mitochondrial EF-G on ribosomes providing support for the reported effect of the drug on parasite mitochondrial translation.
authors.affiliation: Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India.
authors.forename: Ankit
authors.initials: A
authors.lastname: Gupta
authors.affiliation: Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India.
authors.forename: Snober S
authors.initials: SS
authors.lastname: Mir
authors.affiliation: Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India.
authors.forename: Uzma
authors.initials: U
authors.lastname: Saqib
authors.affiliation: Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India.
authors.forename: Subir
authors.initials: S
authors.lastname: Biswas
authors.affiliation: Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India.
authors.forename: Suniti
authors.initials: S
authors.lastname: Vaishya
authors.affiliation: Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, India.
authors.forename: Kumkum
authors.initials: K
authors.lastname: Srivastava
authors.affiliation: Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India.
authors.forename: Mohammad Imran
authors.initials: MI
authors.lastname: Siddiqi
authors.affiliation: Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow, India. Electronic address: saman.habib@gmail.com.
authors.forename: Saman
authors.initials: S
authors.lastname: Habib
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D005672:Fusidic Acid / Q000737:chemistry / Q000494:pharmacology*; D006160:Guanosine Triphosphate / Q000737:chemistry / Q000378:metabolism; D006868:Hydrolysis; D008928:Mitochondria / Q000378:metabolism; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D020653:Peptide Elongation Factor G / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000502:physiology*; D011485:Protein Binding; D014176:Protein Biosynthesis / Q000187:drug effects*; D011487:Protein Conformation; D016415:Sequence Alignment
chemical_list: D020653:Peptide Elongation Factor G; D005672:Fusidic Acid; D006160:Guanosine Triphosphate
keywords: Apicoplast; Elongation factor-G; Fusidic acid; Mitochondria; Plasmodium falciparum; Thiostrepton