Different pressure-temperature behavior of the structured and unstructured regions of titin

► PolyE preserves its disordered characteristics across a wide range of conditions. ► Detailed temperature-pressure phase diagram of titin I27 was determined. ► Phase diagram of titin I27 contains molten globule and aggregated states as well. ► I27 completely unfolds at 65 °C, and a molten globule state is observed at 50 °C. ► Pressure unfolds titin I27 at 10.5 kbar at 30 °C and at 0.9 kbar at 50 °C.