title: Microtubule-associated protein (MAP) 4 interacts with microtubules in an intrinsically disordered manner.
abstract: We previously used nuclear magnetic resonance (NMR) to analyze the structure of a synthetic tricosapeptide corresponding to an active site of microtubule-associated protein 4 (MAP4). To further the structural analysis, we have constructed a minimal active domain fragment of MAP4, encompassing the entire active site, and obtained its NMR spectra. The secondary structure prediction using partially assigned NMR data suggested that the fragment is largely unfolded. Two other independent techniques also demonstrated its unfolded nature, indicating that MAP4 belongs to the class of intrinsically disordered proteins (IDPs). The NMR spectra of the fragment-microtubule mixture revealed that the fragment binds to the microtubule using multiple binding sites, apparently contradicting our previous quantitative studies. Given that MAP4 is intrinsically disordered, we propose a mechanism in which any one of the binding sites is active at a time, which is one of the typical interaction mechanisms proposed for IDPs.
authors: a Faculty of Science, Department of Biological Sciences , Kanagawa University , Hiratsuka , Japan.
authors: Yurika
authors: Y
authors: Hashi
authors: Gota
authors: G
authors: Kawai
authors: Susumu
authors: S
authors: Kotani
mesh_terms: D020134:Catalytic Domain; D009682:Magnetic Resonance Spectroscopy; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000378:metabolism*; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism*; D008954:Models, Biological; D010446:Peptide Fragments / Q000235:genetics*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
chemical_list: D008869:Microtubule-Associated Proteins; D010446:Peptide Fragments
keywords: MAP-microtubule interaction; MAP4; NMR; intrinsically disordered proteins; microtubule