29. Which of the following statements about peptidoglycan is incorrect?
(A) It is the main component of bacterial cell wall, which helps bacteria maintaina certain shape and resist hypotonic environments.
(B) The polysaccharide chain of peptidoglycan is aβ(1-4) linked copolymer of N-acetylglucosamine and N-acetylmuramic acid.
(C) The polysaccharide chains of peptidoglycan are cross-linked together throughtetrapeptides.
(D) One end of the tetrapeptide chain links to a N-acetylglucosamine in thepolysaccharide chain at the C-2 position.
(E) In many Gram negative bacteria, two adjacent tetrapeptide chains are joineddirectly between the e-amino group of lysine in one chain and the carboxyl groupof D-alanine in the other.