This domain is composed of three alpha helices [1]. This domain is found at the N or C terminus of a variety of enzymes involved in bacterial cell wall degradation [2]. This domain may have a general peptidoglycan binding function. This family is found N-terminal to the catalytic domain of matrixins [3]. The domain is found to bind peptidoglycan experimentally [4].

1: Structure of a Zn2+-containing D-alanyl-D-alanine-cleaving carboxypeptidase at 2.5 A resolution. Dideberg O, Charlier P, Dive G, Joris B, Frere JM, Ghuysen JM; Nature 1982;299:469-470. PMID:7121588

2: Cloning, expression, sequence analysis and biochemical characterization of an autolytic amidase of Bacillus subtilis 168 trpC2. Foster SJ; J Gen Microbiol 1991;137:1987-1998. PMID:1683402

3: The NMR structure of the inhibited catalytic domain of human stromelysin-1. Gooley PR, O'Connell JF, Marcy AI, Cuca GC, Salowe SP, Bush BL, Hermes JD, Esser CK, Hagmann WK, Springer JP, et al; Nat Struct Biol 1994;1:111-118. PMID:7656014

4: Muralytic activity and modular structure of the endolysins of Pseudomonas aeruginosa bacteriophages phiKZ and EL. Briers Y, Volckaert G, Cornelissen A, Lagaert S, Michiels CW, Hertveldt K, Lavigne R; Mol Microbiol. 2007;65:1334-1344. PMID:17697255