UB2H is the second domain of the transglycosylases, or penicillin-binding proteins PBP1bs)), the multi-domain membrane proteins essential for cell wall synthesis that are targeted by penicillin antibiotics. The exact function of the UB2H domain is uncertain, but it may act as the binding component of PBP1b with different binding partners, or it may participate in the regulation between DNA repair and/or synthesis and cell wall formation during the bacterial cell cycle.