Molecular Dynamics Reveal Nanosecond Tubulin Conformational Shifts

Molecular dynamics simulations are revealing that tubulin, a fundamental protein involved in cell structure, isn’t static but subtly reshapes itself on timescales of billionths of a second. Chen Xin’s research characterizes the fluctuations of this protein-solvent bath, discovering a tri-exponential statistical property with a surprising nanosecond mode originating from protein conformational rearrangements, not simply water movement. This departs from the commonly assumed “white-noise” model of biological systems, demonstrating that the statistical properties of fluctuations around tryptophan sites fall deep within the non-Markovian regime. The simulations further show this causes Anderson localisation of excitons, confining them to strongly coupled tryptophan pairs, in marked contrast to the more uniform delocalisation predicted by the standard white-noise Haken, Strobl model. Researchers led by Chen Xin have characterized the fluctuations surrounding tryptophan sites…