Dresden 2014 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 5: Protein structure and dynamics I
BP 5.5: Vortrag
Montag, 31. März 2014, 16:00–16:15, ZEU 250
Correlation between Supercoiling and Conformational Motions of the Bacterial Flagellar Filament — •Andreas Stadler1, Tobias Unruh2, Keiichi Namba3, Fadel Samatey4, and Giuseppe Zaccai5 — 1FZ Jülich, ICS-1 & JCNS-1, 52428 Jülich — 2Univ. Erlangen-Nürnberg — 3Osaka University, Osaka, Japan — 4Institute of Science and Technology, Okinawa, Japan — 5Institut Laue-Langevin, Grenoble, France
The bacterial flagellar filament is a very large macromolecular assembly of a single protein flagellin. Various supercoiled states of the filament exist, which are formed by two structurally different conformations of flagellin in different ratios.
We investigated the correlation between supercoiling of the protofilaments and molecular dynamics in the flagellar filament using quasielastic and elastic incoherent neutron scattering in the picosecond and nanosecond time scales. Thermal fluctuations in the straight left- and right-handed (L- and R-type) filaments were measured and compared to the wild-type filament. Amplitudes of motion in the picosecond time scale were found to be similar in the different conformational states. Mean square displacements and protein resilience in the 0.1 nanosecond time scale demonstrate that the L-type state is more flexible and less resilient than the R-type, while the wild-type state lies in between. Our results provide strong support that supercoiling of the protofilaments in the flagellar filament is determined by the strength of molecular forces in and between the flagellin subunits.