Structures of membrane proteins

In reviewing the structures of membrane proteins determined up to the end of2009, we present in words and pictures the most informative examples from each family.We group the structures together according to their function and architecture to provide anoverview of the major principles and variations on the most common themes. The firststructures, determined 20 years ago, were those of naturally abundant proteins with limitedconformational variability, and each membrane protein structure determined was a majorlandmark. With the advent of complete genome sequences and efficient expression systems,there has been an explosion in the rate of membrane protein structure determination, withmany classes represented. New structures are published every month and more than150 unique membrane protein structures have been determined. This review analysesthe reasons for this success, discusses the challenges that still lie ahead, and presents a concisesummary of the key achievements with illustrated examples selected from each class