Proteins systematically lose their protective hydration shell when their environment becomes more acidic. Until recently this was just a theory. State-of-the-art imaging techniques have helped researchers at Martin Luther University Halle-Wittenberg (MLU) directly observe this process for the first time at the level of the individual water molecule. This has answered a question in biochemistry that had remained unanswered for 50 years. In an article published in “Proceedings of the National Academy of Sciences” (PNAS), the team writes that this knowledge could help to develop more stable proteins.