Thermoring-driven allosteric gating coupling in TRPV2

Allosteric regulation of protein activity by chemical stimuli has been extensively investigated, whereas the effects of physical stimuli remain comparatively poorly understood. In this computational study, a highly sensitive thermoring energetic model was employed to analyze the three-dimensional structures of homotetrameric, thermosensitive transient receptor potential vanilloid 2 (TRPV2) channels following a species-specific residue swap near the central lower gate in rat and human TRPV2. In the rat TRPV2 triple mutant, the swap-induced symmetry breaking partially disrupted the interfacial swapping π bridges between the S4-S5 linker and S5’ near the central lower gate. It also altered the location of the superficial weakest tertiary noncovalent bridge and shifted the corresponding melting threshold for heat activation. In contrast, the equivalent residue swap in human TRPV2 preserved C4-fold symmetry, the identity of the superficial weakest bridge and its corresponding melting threshold for heat activation, as well as the interfacial swapping π bridges. Notably, the residue swap in human TRPV2 simultaneously weakened the weakest and swapping bridges, thereby enhancing heat-evoked activity while lowering the heat-activation threshold. Taken together, these findings suggest that when the superficial weakest bridges function as putative heat sensors, C4-fold symmetry is essential for their allosteric gating coupling to the interfacial swapping π bridges. (202 words)