Protein Structure

Structure, including fine details such as isomerism and epimerization, are of interest to the Julian lab. The structural consequences of many chemical modifications occurring in long-lived proteins are not known. We have developed many Mass spectrometry-based (MS) tools for exploring three dimensional protein structure. These methods include radical-based approaches, noncovalent tagging, and most recently, a unique method combining MS with photochemistry to determine distance constraints between specific side chains in peptides and proteins. The data obtained from these experiments can be used to evaluate and even guide calculations, allowing us to evaluate structural effects within a single day. Often these experiments are complemented by synthesis of uniquely modified peptides, enabling us to probe structures not typically considered in most studies.