• cold denaturation
• extreme temperature adaptation
• extremophiles
• neutron scattering
• protein dynamics
• protein stability

This study explores how proteins and cells behave under extreme temperatures to understand molecular adaptations in extremophiles, especially the proteome. We investigated cold denaturation, which is the unfolding of proteins at low temperatures, by using elastic incoherent and quasi-elastic neutron scattering on Yfh1 and lysozyme. In hydrated powders, dynamics remained stable, but in solution, we observed changes that may stem from water freezing rather than true protein behavior.

Small-angle neutron scattering (SANS) was used to study extremophilic bacteria, revealing that morphology changes and cell death correlate with membrane phase transitions. Psychrophiles die below the membrane transition point while hyperthermophiles die above it. The findings connect low-temperature protein instability with high-temperature cellular resilience, showing diverse strategies life uses to survive extreme conditions.

This work highlights the value of neutron scattering in studying biological systems and has implications for cryopreservation and temperature-resistant therapeutics.