Gram negative cell envelope components and transport Chapter 2 Part 2

What are the components of Gram - cell envelope?

(1)Outer membrane

(2)LPS (lipopolysaccharide)

(3)Porins

(4)Ton-B dependent receptors

Outer Membrane

The outermost layer of the Gram-negative cell envelope, composed of lipopolysaccharide (LPS)

Lipopolysaccharide (LPS)

Composed of lipid and polysaccharide. Stabilizes the outer membrane and elicits an inflammatory response in the human body.

LPS components

O-antigen

Core polysaccharide

A-Lipid

Lipid-A

responsible for its endotoxin activity when released during cell

Porins

Proteins embedded in the Gram-negative outer membrane. They form pores that allow diffusion

TonB-dependent Receptors

Proteins embedded in the Gram-negative outer membrane. They catalyze high-affinity active transport of molecules across the outer membrane. (Vitamins)