Atomically detailed structures have always played a key role in understanding the way in which biomolecules carry out their function. But a single atomic structure can never tell the full story, because biomolecules are flexible, and this flexibility mediates function. Single-particle cryo-EM gives us the ability to separate conformations out of a single dataset in silico, combined with enhanced flexibility in the sample preparation process. By carefully tuning grid preparation conditions, and taking advantage of image processing to separate conformational states from single datasets, we aim to weave a mechanistic storyline from our data, with the ultimate goal of reaching atomically-detailed answers to mechanistic questions.
Redox processes in biology
Redox reactions - those in which electrons are transferred - are of central importance to bioenergetics, as well as playing important regulatory and other functions in the cell. Buildling on strengths in electrochemistry and spectroscopy of redox proteins, we are working toward full control of redox potential during the grid-making process. This begins with anaerobic preparation of specimens to prevent oxidation in air, which has allowed us to use the substrates of our protein of interest to alter redox state. Building on this success, we are working toward full and flexible control of the solution potential during grid freezing.
Biomolecules are made up of primarily polypeptide or polynucleotide chains, providing the architecture of these molecules. But the chemistry that can be mediated by the elements of organic matter (H,C,N,O,S,P) is limited. To expand this functionality, many biomolecules bind metals and other ions to take advantage of the sophisticated chemistry that they can carry out. We are interested in better understanding how metals and other bound species mediate and fine-tune protein function.