Different polysaccharide strands are cross-linked by a transpeptidation
reaction involving the pentaglycine bridges.
Van Den Eynde, "Splicing of distant peptide fragments occurs in the proteasome by transpeptidation
and produces the spliced antigenic peptide derived from fibroblast growth factor-5," Journal of Immunology, vol.
They catalyse the exogenous removal of the terminal [gamma]-glutamyl moiety from amides or peptides and its subsequent transfer to water (hydrolysis) or an acceptor amine (transpeptidation
) or a second substrate molecule (autotransfer).
[beta]-lactiun antibiotics such as methicillin bind to proteins responsible for bacterial cell wall synthesis by a mechanism known as transpeptidation
(peptidase enzymes also known as penicillin binding proteins, PBP); thus, if PBP is altered, the [beta]-lactam antibiotic cannot inhibit cell wall formation and the strain is rendered resistant.
PBPs catalyze the final step of polymerization (transglycosylation) and cross-linking by transpeptidation
While in the presence of B-lactam antibiotics, normal PBPs are blocked, PBP2a precedes the transpeptidation
reactions, thereby results in normal cell wall synthesis (8), (10).
This pentapeptide, when incorporated into the nascent peptidoglycan (transglycosylation), permits the formation of cross-bridges (transpeptidation
) and contributes to the strength of the peptidoglycan layer (43).