“…However, pHLIP peptides with a minimum number of protonatable groups and a truncated membrane-inserting end undergo an apparent all-or-none transition for membrane insertion and helix formation ( Karabadzhak et al, 2012 ). Employing the approaches of statistical physics, free-energy landscapes were constructed for pHLIP in membranes at high and low pHs, describing pHLIP’s states ( Sharma et al, 2015 ; Sharma et al, 2022 ). Two viewpoints seem essential: first, the statistical ensemble of different states should always be considered, so one is viewing a predominant subset and not a single state, and second, the kinetics is especially important for in vivo applications in systems with a constant and fast blood flow.…”