The penicillin-binding proteins are bifunctional proteins consisting of transglycosylase and transpeptidase in the N- and C-terminus respectively [1]. The transglycosylase domain catalyses the polymerisation of murein glycan chains ([4]).

1: Topographical and functional investigation of Escherichia coli penicillin-binding protein 1b by alanine stretch scanning mutagenesis. F. Lefevre, M. H. Remy & J. M. Masson; J Bacteriol 1997;179:4761-4767. PMID:9244263

2: X-ray studies of enzymes that interact with penicillins. Kelly JA, Kuzin AP, Charlier P, Fonze E; Cell Mol Life Sci 1998;54:353-358. PMID:9614972

3: Monofunctional biosynthetic peptidoglycan transglycosylases. Spratt BG, Zhou J, Taylor M, Merrick MJ; Mol Microbiol 1996;19:639-640. PMID:8830253

4: The glycosyltransferase domain of penicillin-binding protein 2a from Streptococcus pneumoniae catalyzes the polymerization of murein glycan chains. Di Guilmi AM, Dessen A, Dideberg O, Vernet T; J Bacteriol 2003;185:4418-4423. PMID:12867450