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BP: Fachverband Biologische Physik

BP 1: Protein Structure and Dynamics

BP 1.2: Vortrag

Montag, 12. März 2018, 10:00–10:15, H 1028

Short-time self-dynamics of immunoglobulin under bio-mimicking crowding conditions — •Marco Grimaldo¹, Beck Christian^1,2, Felix Roosen-Runge³, Fajun Zhang², Frank Schreiber², and Tilo Seydel¹ — ¹Institut Laue-Langevin, Grenoble, France — ²IAP- Universität Tübingen, Tübingen, Germany — ³Division for Physical Chemistry, Lund University, Lund, Sweden

Approximately 10-40% of the intra- and extracellular fluids of living organisms are occupied by macromolecules such as proteins. This macromolecular crowding condition was shown to influence reaction rates, and to lead to anomalous diffusion. We present a neutron backscattering study on the pico- to nanosecond self-diffusion and internal motion of the antibody proteins immunoglobulins (Ig) in aqueous environment. To systematically investigate the effect of macromolecular crowding on protein dynamics we vary the concentration of cellular lysate, mimicking a cellular environment. The dynamics of Ig in lysate is then compared with that of Ig in pure (heavy) water as a function of its own concentration (self-crowding) [1]. Despite the high polydispersity and the not easily predictable variance in lysate composition, both the measured diffusion and the localized internal atomic motion of Ig as a function of the overall volume fraction are in rather good agreement with those of Ig in the self-crowded environment at comparable volume fraction, suggesting a crucial role of hydrodynamic interactions on short-time protein dynamics even in a cell-like environment.
Grimaldo M., Roosen-Runge F., Zhang F., Seydel T., Schreiber F. JPCB 118 (2014): 7203.