Many experimental approaches use surfactants or detergents to decrease protein aggregation, or to solubilise membrane proteins during the purification process. This is particularly important in X-ray crystallography of membrane proteins and proteins that form fibrils and aggregates. Environmental conditions such as salt concentration and pH are also modified in many cases to induce protein crystallisation. Other chemical modifications, such as the PEGylation of proteins, drugs and hormones, are used for a range of therapeutic and industrial applications, from extending the half-life of drugs and therapeutic agents, to anti-fouling paints. Our goal is to understand how these experimental conditions or chemical modifications influence the conformation of a protein, and how this relates to its native conformation.