Question

A species of infectious bacteria secrets a toxin which disrupts the intramolecular interactions between the constituents of polypeptide backbones. Which level(s) of protein structure will this toxin disrupt?

Answer 1

The bacteria are envoloped by a cell wall that consists of a polypeptide backbone of peptidoglycans. Peptidoglycans mainly consists of sugars and amino acids forming a protective layer outside the plasma membrane. The sugar component mainly consists of alternating residues of β-(1,4) linked N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). Attached to NAM is a peptide chain of three to five amino acids long. MreB is a protein mainly found in the cell wall of bacteria that renders the cell shape to the bacterium. Therefore, the toxin if disrupts the peptidoglycan backbone will result in destruction of the protein MreB. Also the levels of S-layer proteins will disrupt.