title: The compact conformation of the Plasmodium knowlesi myosin tail interacting protein MTIP in complex with the C-terminal helix of myosin A.
abstract: The myosin motor of the malaria parasite's invasion machinery moves over actin fibers while it is making critical contacts with the myosin-tail interacting protein (MTIP). Previously, in a "compact" Plasmodium falciparum MTIP•MyoA complex, MTIP domains 2 (D2) and 3 (D3) make contacts with the MyoA helix, and the central helix is kinked, but in an "extended" Plasmodium knowlesi MTIP•MyoA complex only D3 interacts with the MyoA helix, and the central helix is fully extended. Here we report the crystal structure of the compact P. knowlesi MTIP•MyoA complex. It appears that, depending on the pH, P. knowlesi MTIP can adopt either the compact or the extended conformation to interact with MyoA. Only at pH values above ~7.0, can key hydrogen bonds can be formed by the imidazole group of MyoA His810 with an aspartate carboxylate from the hinge of MTIP and a lysine amino group of MyoA simultaneously.
authors.affiliation: Department of Biochemistry, Biomolecular Structure Center, School of Medicine, University of Washington, Seattle, WA 98195, USA.
authors.forename: Stewart
authors.initials: S
authors.lastname: Turley
authors.forename: Susmita
authors.initials: S
authors.lastname: Khamrui
authors.forename: Lawrence W
authors.initials: LW
authors.lastname: Bergman
authors.forename: Wim G J
authors.initials: WG
authors.lastname: Hol
mesh_terms: D018360:Crystallography, X-Ray; D003598:Cytoskeletal Proteins / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D016790:Plasmodium knowlesi / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation / Q000187:drug effects
chemical_list: D003598:Cytoskeletal Proteins
keywords: D2; D3; GAP; Glideosome; Invasion; MTIP; Malaria; PfalMTIP; PknoMTIP; Plasmodium falciparum MTIP; Plasmodium knowlesi MTIP; TRAP; X-ray structure; domain 2 of MTIP; domain 3 of MTIP; glideosome-associated protein; myosin-tail interacting protein; rmsd; root mean square deviation; thrombospondin-related anonymous protein.