title: Starmaker exhibits properties of an intrinsically disordered protein.
abstract: Fish otoliths composed of calcium carbonate and an organic matrix play a primary role in gravity sensing and the perception of sound. Starmaker (Stm) was the first protein found to be capable of influencing the process of biomineralization of otoliths. Stm dictates the shape, size, and selection of calcium carbonate polymorphs in a concentration-dependent manner. To facilitate exploration of the molecular basis of Stm function, we have developed and optimized a protocol for efficient expression and purification of the homogeneous nontagged Stm. The homogeneous nontagged Stm corresponds to its functional form, which is devoid of a signal peptide. A comprehensive biochemical and biophysical analysis of recombinant Stm, along with in silico examinations, indicate for the first time that Stm exhibits the properties of intrinsically disordered proteins. The functional significance of Stm having intrinsically disordered protein properties and its possible role in controlling the formation of otoliths is discussed.
authors.affiliation: Department of Biochemistry, Faculty of Chemistry, Wrocław University of Technology, Wrocław, Poland.
authors.forename: Tomasz M
authors.initials: TM
authors.lastname: Kapłon
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Rymarczyk
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Nocula-Ługowska
authors.forename: Michał
authors.initials: M
authors.lastname: Jakób
authors.forename: Marian
authors.initials: M
authors.lastname: Kochman
authors.forename: Marek
authors.initials: M
authors.lastname: Lisowski
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Szewczuk
authors.forename: Andrzej
authors.initials: A
authors.lastname: Ozyhar
mesh_terms: D000818:Animals; D001703:Biophysics / Q000379:methods; D002119:Calcium Carbonate / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D005399:Fishes; D005822:Genetic Vectors; D010037:Otolithic Membrane / Q000502:physiology*; D011487:Protein Conformation; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000737:chemistry*
chemical_list: D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D029961:Zebrafish Proteins; C478248:stm protein, zebrafish; D002119:Calcium Carbonate