Crystallography beyond Crystals: PX and SPCryoEM

Protein Crystallography (PX) or Macromolecular Crystallography has been unarguably one of the great intellectual achievements of 20th century. In fact, it has developed to be a strong base for ‘hybrid methods’ for macromolecular structure determination by a combination of PX and Single Particle Cryo Electron Microscopy (SPCryoEM). This article describes how PX and SPCryoEM are independent methods, how they contribute as hybridmethods, their complementarity and supplementarity and their current status. This article though not a complete review of PX or SPCryoEMof macromolecular protein complexes, serves as a guideline in understanding the underlying principles.