生体分子凝縮液における普遍的な粘弾性シグネチャをエンコードするバックボーン剛性

Biomolecular condensates exhibit a wide range of viscoelastic properties, shaped by their molecular sequences and compositions. Coarse-grained molecular models of intrinsically disordered proteins are widely used to complement experimental data by revealing the structures and thermodynamics of condensates. However, fully flexible chain representations of intrinsically disordered proteins often fail to capture their complex viscoelastic behavior, instead predicting purely viscous responses. In this work, we demonstrate that introducing sequence-dependent chain rigidity enables us to reproduce the experimentally observed trends in the elastic and viscous moduli for A1-LCD condensates and their variants. Furthermore, we show that the frequency-dependent loss factor can be characterized by a single descriptor that correlates with viscosity across A1-LCD variants and diverse parameter settings within a single-bead, semiflexible coarse-grained model. We further find that increasing backbone rigidity expands the elastic-dominated frequency range and is accompanied by more extended condensate-phase conformations. Finally, we elucidate the microscopic origins of sequence-encoded viscoelasticity by demonstrating how it can be tuned through sequence rearrangements that promote the formation of sticker clusters.