The research proposed aims to provide a better understanding of how membrane proteins acquire their final structures. The experiments will examine the roles of three sequence elements in determining the membrane structure of the E. coli serine chemoreceptor. The experiments will determine whether interactions between membrane- spanning sequences can contribute to their membrane insertion. It will also examine how an amphipathic sequence adjacent to one of the spanning sequences controls that sequence's membrane orientation. Additional experiments will examine how mutations altering sequences required for membrane insertion affect later stages in serine chemoreceptor assembly.