Cephalexin is a cephalosporin antibiotic used to study the effect of expression, binding, and inhibition of PBP3 and other penicillin-binding proteins (PBPs) on bacterial cell wall mucopeptide synthesis. Cephalexin disrupts the synthesis of the peptidoglycan layer of bacterial cell walls which is responsible for cell wall structural integrity. Peptidoglycan synthesis is facilitated by transpeptidases known as penicillin-binding proteins (PBPs). PBPs bind to the D-Ala-D-Ala at the end of muropeptides (peptidoglycan precursors) to crosslink the peptidoglycan. Cephalexin antibiotics mimic the D-Ala-D-Ala site, thereby competitively inhibiting PBP crosslinking of peptidoglycan.
