2A-2
The Role of Hydroxyl Groups in Proton Conduction: From Dipeptides to Proteins, H. Semizo (Setsunan Uni.) et al.

Hydroxyl groups are expected to play a key role in proton conduction by controlling hydration structures and hydrogen-bond networks. In this study, Gly-Hyp crystals were prepared and compared with Gly-Pro crystals to clarify the contribution of hydroxyl groups to proton conduction. The proton conductivity of Gly-Hyp increased stepwise with hydration number, indicating that hydrated water promotes proton transport. Dielectric analysis revealed cooperative motion of side chains and hydrated water, suggesting that dipole reorientation in the hydration shell contributes to proton conduction. Structural comparison showed that Gly-Hyp possesses a higher density of hydrogen-bond donor sites than Gly-Pro. These findings provide molecular design guidelines for Ser-based recombinant protein proton conductors.