Coherent X-rays reveal anomalous molecular diffusion and cage effects in crowded protein solutions.

ABSTRACT: Understanding protein motion within the cell is crucial for predicting reaction rates and macromolecular transport in the cytoplasm. A key question is how crowded environments affect protein dynamics through hydrodynamic and direct interactions at molecular length scales. Using megahertz X-ray Photon Correlation Spectroscopy (MHz-XPCS) at the European X-ray Free Electron Laser (EuXFEL), we investigate ferritin diffusion at microsecond time scales. Our results reveal anomalous diffusion, indicated by the non-exponential decay of the intensity autocorrelation function g₂(q, t) at high concentrations. This behavior is consistent with the presence of cage-trapping between the short- and long-time protein diffusion regimes. Modeling with the δγ-theory of hydrodynamically interacting

SUBMITTER: Girelli A 

PROVIDER: S-EPMC12669764 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature