PMID:11427528

Citation	Rau, A, Hogg, T, Marquardt, R and Hilgenfeld, R (2001) A new lysozyme fold. Crystal structure of the muramidase from Streptomyces coelicolor at 1.65 A resolution. J. Biol. Chem. 276:31994-9
Abstract	Cellosyl is a bacterial muramidase from Streptomyces coelicolor. Similar to other lysozymes, the enzyme cleaves the beta-1,4-glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine units, but it also exhibits a beta-1,4-N,6-O-diacetylmuramidase activity. The latter enables Cellosyl to degrade the cell walls of Staphylococcus aureus, which are not hydrolyzed by chicken-, goose-, or bacteriophage T4-type lysozymes. The enzymatic activity and amino acid sequence of Cellosyl group it with lysozymes of the Chalaropsis type, for which no detailed structural information has been available so far. The crystal structure of Cellosyl from S. coelicolor has been determined to a resolution of 1.65 A and refined to an R-factor of 15.2%. The enzyme is comprised of a single domain and possesses an unusual beta/alpha-barrel fold. The last strand, beta 8, of the (beta/alpha)(5)beta(3)-barrel is found to be antiparallel to strands beta 7 and beta 1. Asp-9, Asp-98, and Glu-100 are located at the active site. The structure of Cellosyl exhibits a new lysozyme fold and represents a new class of polysaccharide-hydrolyzing beta/alpha-barrels.
Links	PubMed Online version:10.1074/jbc.M102591200
Keywords	Amino Acid Sequence; Carbohydrate Sequence; Crystallography, X-Ray; Models, Molecular; Molecular Sequence Data; Muramidase/chemistry; Protein Conformation; Protein Folding; Sequence Homology, Amino Acid; Streptomyces/enzymology
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
STRGL:LYSM1		0008152: metabolic process	ECO:0000314:		P		The metabolic process has to do with the structure of the overall protein. The structure of Cellosyl comprised to a single domain,is demonstrated in figure 2. Where it is shown that the structure is comprised of eight beta strands and six alpha helices. Shown with the strands forming the staves of the barrel and the helices located around it. Helices are depicted in red, loops in green, the parallel βeta-strands in blue, and the antiparallel βeta-strand is highlighted in yellow.	complete CACAO 12878
STRGL:LYSM1		GO:0003796: lysozyme activity	ECO:0000314:		F		Figure 1 displays that unlike other lysozymes (HEWL, GEWL, and T4L-types), the Ch-type lysozymes have both Beta-1,4-N-acetyl- and Beta-1,4,-N,6-O-diacetylmuramidase activities. Due to this characteristic they are able to cleave the 6-O-acetylated peptidoglycans. This icnludes the peptiodglycans that are present in cell walls of Staphylococcus aureus. Figure 2 displays that the structure of Cellosyl contributes to its function. Figure two shows that Cellosyl comprises a single domain. The enzyme is shown to have a beta/alpha-barrel fold. This is different than many other enzymes which have (Beta/alpha)8-barrels. All of these specific folds allow for the active site to be locate at the C-terminal end of the beta-barrel. Figure 3 compares the amino acid sequence of various Ch-type lysozymes and it supports that the active site is located at the C-terminal end of the Beta-barrel. It does so because it shows that the amino acids at the C-terminal ends of Beta1 and Beta4 are highly conserved among lysozymes from bacteria and Chalaropsis. Figure 4 displays how the charges are distributed on the surface of Cellosyl and how that impacts it's lysozyme activity. Due to the grove in the substrate-binding site, there is a high negative electrostatic potential. This is developed to the deep hole.	complete CACAO 12908
STRGL:LYSM1	Contributes to	GO:0003796: lysozyme activity	ECO:0000255:	UniProtKB:P25310	F		Figure 1 shows four different classes of endo-N-acetylmuramidases which all use lysosome structures and this is presented in the cellosyl. This shows that lysozyme activity is being used.	complete CACAO 12911

References

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