title: Ferritin Assembly Revisited: A Time-Resolved Small-Angle X-ray Scattering Study.
abstract: The assembly reaction of Escherichia coli ferritin A (EcFtnA) was studied using time-resolved small-angle X-ray scattering (TR-SAXS). EcFtnA forms a cagelike structure that consists of 24 identical subunits and dissociates into dimers at acidic pH. The dimer maintains nativelike secondary and tertiary structures and is able to reassemble into a 24-mer when the pH is increased. The reassembly reaction was induced by pH jump, and reassembly was followed by TR-SAXS. Time-dependent changes in the forward scattering intensity and in the gyration radius suggested the existence of a significant population of intermediate oligomers during the assembly reaction. The initial reaction was a mixture of second- and third-order reactions (formation of tetramers and hexamers) from the protein concentration dependence of the initial velocity. The time-dependent change in the SAXS profile was roughly explained by a simple model in which only tetramers, hexamers, and dodecamers were considered as intermediates.
authors.affiliation: Department of Bioinformatics, Soka University , 1-236 Tangi-machi, Hachioji, Tokyo 192-8577, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sato
authors.affiliation: Department of Bioinformatics, Soka University , 1-236 Tangi-machi, Hachioji, Tokyo 192-8577, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Ohtomo
authors.affiliation: SPring-8, Japan Synchrotron Radiation Research Institute , 1-1-1 Kouto, Sayo, Hyogo 679-5189, Japan.
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Yamada
authors.affiliation: RIKEN SPring-8 Center , 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Hikima
authors.affiliation: Department of Bioinformatics, Soka University , 1-236 Tangi-machi, Hachioji, Tokyo 192-8577, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kurobe
authors.affiliation: Department of Bioinformatics, Soka University , 1-236 Tangi-machi, Hachioji, Tokyo 192-8577, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Fujiwara
authors.affiliation: Department of Bioinformatics, Soka University , 1-236 Tangi-machi, Hachioji, Tokyo 192-8577, Japan.
authors.forename: Masamichi
authors.initials: M
authors.lastname: Ikeguchi
mesh_terms: D005293:Ferritins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D005293:Ferritins