Five new membrane protein structures have been determined since 1995 using X-ray crystallography: bacterial light-harvesting complex; bacterial and mitochondrial cytochrome c oxidases; mitochondrial bc1 complex; and α-hemolysin. These successes are partly based on advances in the crystallization procedures for integral membrane proteins. Variation of the size of the detergent micelle and/or increasing the size of the polar surface of the membrane protein is the most important route to well-ordered membrane protein crystals. The use of bicontinuous lipidic cubic phases also appears to be promising.
