MIMM 211 Lecture Notes - Lecture 7: Periplasm, Ribitol, Peptidoglycan
13 Dec 2018
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In gram +ve cells, the cell wall also contains teichoic acid (glycerol or ribitol polymers) that runs perpendicular to the peptidoglycan chains: acts to solidify its structure. In gram +ve cells (no outer membrane), the cell wall is anchored to the cytoplasmic membrane by lipoteichoic acid. In gram -ve cells, the cell wall is anchored to the outer membrane by lipoproteins. Notice that there are lipid tails on the teichoic acid. These lipid tails are embedded in the membrane. They are not covalently bound so that the membrane can still be fluid. The lipid tails form hydrophobic interactions with the membrane. Conversely, the acid portion forms covalent bonds with the peptidoglycan layers. We can see that the peptidoglycan layer is bound to the outer membrane through the interaction with the lipoproteins. The protein part interacts with the peptidoglycan and a portion of it spans the periplasmic space (hydrophilic)
