InterPro domain: IPR008258

Bacterial lytic transglycosylases degrade murein via cleavage of the beta-1,4-glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine, with the concomitant formation of a 1,6-anhydrobond in the muramic acid residue. There are both soluble (Slt enzymes) and membrane-bound (Mlt enzymes) lytic transglycosylases that differ in size, sequence, activity, specificity and location. The multi-domain structure of the 70 Kd soluble lytic transglycosylase Slt70 is known [ 1 ]. Slt70 has 3 distinct domains, each rich in alpha helices: an N-terminal superhelical U-shaped domain, a superhelical linker domain (L-domain, IPR012289 ), and a C-terminal catalytic domain ( IPR023346 ). Both the U- and L-domain share a similar superhelical structure. These two domains are connected, and together form a closed ring with a large central hole; the catalytic domain is packed on top of, and interacts with, this ring. The catalytic domain has a lysosome-like fold.

This domain is found mainly in proteins from phages and type II, type III and type IV secretion systems [ 2 , 3 , 4 , 5 ].

1. High resolution crystal structures of the Escherichia coli lytic transglycosylase Slt70 and its complex with a peptidoglycan fragment. J. Mol. Biol. 291, 877-98
2. A conserved domain in putative bacterial and bacteriophage transglycosylases. Trends Biochem. Sci. 19, 106-7
3. A family of lysozyme-like virulence factors in bacterial pathogens of plants and animals. Proc. Natl. Acad. Sci. U.S.A. 93, 7321-6
4. Lytic transglycosylases in macromolecular transport systems of Gram-negative bacteria. Cell. Mol. Life Sci. 60, 2371-88