What are the components of gram-negative cell walls?

Gram-negative cell walls are composed of an outer membrane, a peptidoglycan layer, and a periplasm. Gram-negative bacteria have a single, thin peptidoglycan layer measuring about 10 nanometers. The single layer of peptidoglycan is surrounded by a membranous structure called the outer membrane, which contains lipopolysaccharide (LPS), proteins and phospholipids. The lipopolysaccharide component is toxic and acts as a virulence factor, causing diseases in animals. The periplasm, which lies sandwiched between the outer membrane and the plasma membrane, appears as a concentrated gel-like matrix and contains binding proteins for enzymes, sugars, amino acids, iron, and vitamins essential for bacterial nutrition. It also acts as a reservoir for some virulence factors.