Membrane Protein Crystallization From Cubic Lipid Matrices

Protein crystallographyJust like minerals and salts, proteins can form crystals. And, justlike other crystals, proteins will diffract X-rays. From the X-raysdiffraction patterns, the protein structures can be determined.X-ray diffraction images of bacteriorhodopsin crystals, (3)However, proteins are much harder to grow than salts, andby 1975 only 37 structures had been placed in the ProteinData Bank. These crystals tend to be extremely fragileand sensitive to conditions such as pH, specific ionconcentrations, and other factors. They are also easilydamaged by the X-rays used to probe their structure.Now, as techniques of growing crystals and inverting the X-ray scattering data haveimproved, more than 12,000 structures have been posted to the PDB.bR crystals surrounded by lipids, (5)