Assembly Mechanism of Trypanosoma brucei BILBO1, a Multidomain Cytoskeletal Protein |
| |
Authors: | Keni Vidilaseris Ekaterina Shimanovskaya Heather J Esson Brooke Morriswood Gang Dong |
| |
Institution: | From the Max F. Perutz Laboratories, University of Vienna and Medical University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria |
| |
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. |
| |
Keywords: | Calcium-binding Protein Cytoskeleton Electron Microscopy (EM) Protein Assembly Trypanosoma brucei EF-hand Leucine Zipper TbBILBO1 Coiled Coil Flagellar Pocket Collar |
|
|