title: EWGWS insert in Plasmodium falciparum ookinete surface enolase is involved in binding of PWWP containing peptides: Implications to mosquito midgut invasion by the parasite.
abstract: There are multiple stages in the life cycle of Plasmodium that invade host cells. Molecular machinery involved is such host-pathogen interactions constitute excellent drug targets and/or vaccine candidates. A screen using a phage display library has previously demonstrated presence of enolase on the surface of the Plasmodium ookinete. Phage-displayed peptides that bound to the ookinete contained a conserved motif (PWWP) in their sequence. Here, direct binding of these peptides with recombinant Plasmodium falciparum enolase (rPfeno) was investigated. These peptides showed specific binding to rPfeno, but failed to bind to other enolases. Plasmodium spp enolases are distinct in having an insert of five amino acids ((104)EWGWS(108)) that is not found in host enolases. The possibility of this insert being the recognition motif for the PWWP containing peptides was examined, (i) by comparing the binding of the peptides with rPfeno and a deletion variant Δ-rPfeno lacking (104)EWGWS(108), (ii) by measuring the changes in proton chemical shifts of PWWP peptides on binding to different enolases and (iii) by inter-molecular docking experiment to locate the peptide binding site. Results from these studies showed that the pentapeptide insert of Pfeno indeed constitutes the binding site for the PWWP domain containing peptide ligands. Search for sequences homologous to phage displayed peptides among peritrophic matrix proteins resulted in identification of perlecan, laminin, peritrophin and spacran. The possibility of these PWWP domain-containing proteins in the peritrophic matrix of insect gut to interact with ookinete cell surface enolase and facilitate the invasion of mosquito midgut epithelium is discussed.
authors.affiliation: Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India.
authors.forename: Debanjan
authors.initials: D
authors.lastname: Mukherjee
authors.affiliation: Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India.
authors.forename: Pushpa
authors.initials: P
authors.lastname: Mishra
authors.affiliation: Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India.
authors.forename: Mamata
authors.initials: M
authors.lastname: Joshi
authors.affiliation: Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisbon, 1649- 028 Lisbon, Portugal.
authors.forename: Prasoon Kumar
authors.initials: PK
authors.lastname: Thakur
authors.affiliation: Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India.
authors.forename: R V
authors.initials: RV
authors.lastname: Hosur
authors.affiliation: Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India. Electronic address: gkjarori@gmail.com.
authors.forename: Gotam K
authors.initials: GK
authors.lastname: Jarori
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D009033:Culicidae / Q000469:parasitology*; D004064:Digestive System / Q000378:metabolism; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D019151:Peptide Library; D010455:Peptides / Q000378:metabolism; D010751:Phosphopyruvate Hydratase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010963:Plasmodium falciparum / Q000201:enzymology*; D011485:Protein Binding; D011487:Protein Conformation; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D019476:Insect Proteins; D019151:Peptide Library; D010455:Peptides; D015800:Protozoan Proteins; D011994:Recombinant Proteins; D010751:Phosphopyruvate Hydratase
keywords: Enolase; ITC; Molecular docking; NMR; Ookinete; P. falciparum