title: Cell wall-targeting domain of glycylglycine endopeptidase distinguishes among peptidoglycan cross-bridges.
abstract: ALE-1, a homologue of lysostaphin, is a peptidoglycan hydrolase that specifically lyses Staphylococcus aureus cell walls by cleaving the pentaglycine linkage between the peptidoglycan chains. Binding of ALE-1 to S. aureus cells through its C-terminal 92 residues, known as the targeting domain, is functionally important for staphylolytic activity. The ALE-1-targeting domain belongs to the SH3b domain family, the prokaryotic counterpart of the eukaryotic SH3 domains. The 1.75 angstroms crystal structure of the targeting domain shows an all-beta fold similar to typical SH3s but with unique features. The structure reveals patches of conserved residues among orthologous targeting domains, forming surface regions that can potentially interact with some common features of the Gram-positive cell wall. ALE-1-targeting domain binding studies employing various bacterial peptidoglycans demonstrate that the length of the interpeptide bridge, as well as the amino acid composition of the peptide, confers the maximum binding of the targeting domain to the staphylococcal peptidoglycan. Truncation of the highly conserved first 9 N-terminal residues results in loss of specificity to S. aureus cell wall-targeting, suggesting that these residues confer specificity to S. aureus cell wall.
authors.affiliation: Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, USA.
authors.forename: Jeff Zhiqiang
authors.initials: JZ
authors.lastname: Lu
authors.forename: Tamaki
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Komatsuzawa
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Sugai
authors.forename: Joshua
authors.initials: J
authors.lastname: Sakon
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D002473:Cell Wall / Q000201:enzymology*; D018360:Crystallography, X-Ray; D010450:Endopeptidases / Q000737:chemistry* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010457:Peptidoglycan / Q000378:metabolism; D017434:Protein Structure, Tertiary; D013211:Staphylococcus aureus / Q000201:enzymology*; D018909:src Homology Domains
chemical_list: D001426:Bacterial Proteins; D010457:Peptidoglycan; D010450:Endopeptidases; C120985:LytM protein, Staphylococcus aureus