Solution structure of the loops of bacteriorhodopsin closely resembles thecrystal structure

Bacteriorhodopsin is one of very few transmembrane proteins for which high resolution structures have been solved. The structure shows a bundle of sev en helices connected by six turns. Some turns in proteins are stabilized by short range interactions and can behave as small domains. These observatio ns suggest that peptides containing the sequence of the turns in a membrane protein such as bacteriorhodopsin may form stable turn structures in solut ion. To test this hypothesis, we determined the solution structure of three peptides each containing the sequence of one of the turns in bacteriorhodo psin. The solution structures of the peptides closely resemble the structur es of the corresponding turns in the high resolution structures of the inta ct protein. (C) 2000 Elsevier Science B.V. All rights reserved.