Interdomain linkers tune the energy dissipation of immunoglobulin domains in titin

Mechanical forces are central to biological function, with mechanosensitive multidomain proteins (MDPs) such as titin translating strain into adaptive responses. While damping is well recognized at the tissue level in muscles, how it emerges from a multidomain protein connected by interdomain linkers (IDLs) has remained unclear. Here, using magnetic tweezers, we probe engineered titin I27 dimers connected by three distinct synthetic linkers (RS, GG, and GGGSGGGG) under both equilibrium constant force clamp and far-from-equilibrium oscillatory force pulse protocols. We show that folded domains exhibit unfolding along with deformations under load and that IDLs act as molecular regulators of damping. Rigid linkers promote stepwise, cooperative unfolding and faster energy dissipation, showing overdamped response, whereas flexible linkers favor gradual, viscoelastic transitions with energy-conserving underdamped behavior. Furthermore, increased domain stability correlates with enhanced damping capacity. Our work provides experimental evidence of single protein-level damping, revealing how nature encodes long-term durability into its molecular machines.