The molecular origin of body temperature in homeothermic species
We propose the Interfacial Water Quantum-transition model (IWQ model) explaining temperature-dependent functional transitions in proteins. The model postulates that measured critical temperatures, TC, correspond to reference temperatures, TW, defined by rotational quantum transitions of temporarily free water molecules at the protein-water interface. The models applicability is demonstrated through transitions in hemoglobin and thermosensitive TRP channels. We suggest this mechanism also defines basal body temperatures in homeotherms, with TW=36.32{degrees}C for humans. We demonstrate that human (mammal) and chicken (Aves) body temperatures align with specific reference temperatures, and correlate with pronounced transitions at TC in hemoglobin oxygen saturation. This suggests evolutionary adaptations in homeotherms involve an interplay between oxygen supply and waters rotational transition temperatures. The IWQ-model states that proteins sense and water sets critical physiological temperatures. Significance StatementWe propose the Interfacial Water Quantum-transition (IWQ) model that offers a new way to understand how proteins respond to critical temperature changes. We suggest that the key temperatures at which proteins change their function are linked to specific quantum transitions of water molecules at the protein-water interface. This model explains why certain critical temperatures, like human body temperature, align with these transitions. By exploring this connection in proteins like hemoglobin and in thermosensitive channels, the IWQ model highlights a fundamental link between water behavior and biological temperature regulation, shedding light on evolutionary adaptations in humans and other animals.