Is one solution good enough?

Three-dimensional structures of proteins, nucleic acids and other macromolecules are central to understanding biology. In macromolecular crystallography, it is conventional to represent the conformation of a macromolecule as a single structure unless strong evidence is available for specific alternative conformations. This convention unfortunately results in little indication of either accuracy or conformational heterogeneity in the crystal structures deposited in the Protein Data Bank (PDB).