It is the over-all objective of this work to gain an understanding in molecular terms of the coordinated process of the assembly of membrane lipids and membrane proteins into functional units. The principal specific goals of the work are the following: I. Structure and Function of Novel Oligosaccharides of Escherichia coli Derived from Membrane Lipids. It is proposed to elucidate the chemical structure of these oligosaccharides, and to determine the pathways of their biogenesis, and to explore their function in suitable mutants. II. Genetic Regulation of the Synthesis of Membrane Lipids. Particular attention will be paid to the regulation of phosphatidylserine synthetase and phosphatidylserine decarboxylase. The effects of altered lipid composition on membrane function will be investigated. III. Molecular Architecture of an Intrinsic Membrane Protein: Phosphatidylserine Decarboxylase. A combined chemical and genetic approach will be used to explore the relations between the structure of this protein and its membrane localization and function.