title: Assembly mechanism of Trypanosoma brucei BILBO1, a multidomain cytoskeletal protein.
abstract: Trypanosoma brucei BILBO1 (TbBILBO1) is an essential component of the flagellar pocket collar of trypanosomes. We recently reported the high resolution structure of the N-terminal domain of TbBILBO1. Here, we provide further structural dissections of its other three constituent domains: EF-hand, coiled coil, and leucine zipper. We found that the EF-hand changes its conformation upon calcium binding, the central coiled coil forms an antiparallel dimer, and the C-terminal leucine zipper appears to contain targeting information. Furthermore, interdimer interactions between adjacent leucine zippers allow TbBILBO1 to form extended filaments in vitro. These filaments were additionally found to condense into fibers through lateral interactions. Based on these experimental data, we propose a mechanism for TbBILBO1 assembly at the flagellar pocket collar.
authors.affiliation: From the Max F. Perutz Laboratories, University of Vienna and Medical University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
authors.forename: Keni
authors.initials: K
authors.lastname: Vidilaseris
authors.affiliation: From the Max F. Perutz Laboratories, University of Vienna and Medical University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Shimanovskaya
authors.affiliation: From the Max F. Perutz Laboratories, University of Vienna and Medical University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Esson
authors.affiliation: From the Max F. Perutz Laboratories, University of Vienna and Medical University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria brooke.morriswood@univie.ac.at.
authors.forename: Brooke
authors.initials: B
authors.lastname: Morriswood
authors.affiliation: From the Max F. Perutz Laboratories, University of Vienna and Medical University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria gang.dong@meduniwien.ac.at.
authors.forename: Gang
authors.initials: G
authors.lastname: Dong
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000378:metabolism*; D019281:Dimerization; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000737:chemistry / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014346:Trypanosoma brucei brucei / Q000378:metabolism*
chemical_list: D003598:Cytoskeletal Proteins; D015800:Protozoan Proteins
keywords: Calcium-binding Protein; Coiled Coil; Cytoskeleton; EF-hand; Electron Microscopy (EM); Flagellar Pocket Collar; Leucine Zipper; Protein Assembly; TbBILBO1; Trypanosoma brucei