Bacterial lytic transglycosylases degrade murein via cleavage of the beta-1,4-glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine, with theconcomitant formation of a 1,6-anhydrobond in the muramic acid residue.<taxon tax_id="562">Escherichia coli</taxon> has at least three different lytic transglycosylases: twosoluble isozymes of 65 Kd and 35 Kd and a membrane-bound enzyme of 38 Kd. Thesequence of the 65 Kd enzyme (gene slt) has been determined [<cite idref="PUB00002156"/>]. A domain ofabout 90 residues located near the C-terminal section of slt was recentlyshown to be present in a number of other prokaryotic and phage proteins [<cite idref="PUB00005413"/>].This SLT domain shared by these proteins is involved in catalyticactivity. The most conserved part of this domain contains the contains two conserved serines and aglutamate which form part of this active site signature [<cite idref="PUB00004171"/>, <cite idref="PUB00000408"/>]. Prokaryotic transglycosylase, active site