What biological questions can we answer with volume matching?

The central tenet of structural biology is that macromolecular structure determines biological function. While function is often inferred from sequence information, it is the three dimensional structure of the protein or RNA that actually performs the function. This idea still holds even if the atomic structure (and hence chemistry) of the macromolecule is unknown.

Volume data can reveal details of biological function, and matching volumes between two datasets will detail similarities and differences in these functions. Specific examples include:

• Stoichiometry of complexes – the number of each molecule type contributing to the full complex. This can vary during the life cycle of the complex
• Binding of ligands – whether a particular ligand binds, and then the location of the binding site
• Conformational changes – macromolecules are flexible, and comparisons can reveal changes under certain conditions, or a range of conformations for one condition
• Similarity of function or binding partners – conserved shape may imply conserved function