Structure and function of the cell envelope of gram negative bacteria

Abstract

The structural organization of the gram negative cell envelope is described. The cytoplasmic membrane has been shown to have a chemical composition similar to that of other biological membranes. At the outer surface of the cytoplasmic membrane certain enzymes are located. The peptidoglycan layer exerts morphological control over the cytoplasmic elements of the cell and forms, covalently linked with lipoproteins, the inelastic foundation of the whole cell envelope. The periplasmic zone is assumed to bind enzymes, smaller molecules and ions. The outer membrane layer consists of a protruding pattern of lipopolysaccharide oligosaccharides between which the proteins and phospholipids are exposed. Cell wall synthesis is performed by releasing structural subunits and the enzymes, responsible for their final structural binding, at the cytoplasmic membrane. The function of some enzymes that are associated with the cell wall is discussed.