title: Calcium-dependent complex formation between PBP2 and lytic transglycosylase SltB1 of Pseudomonas aeruginosa.
abstract: In Gram-negative bacteria, the bacterial cell wall biosynthetic mechanism requires the coordinated action of enzymes and structural proteins located in the cytoplasm, within the membrane, and in the periplasm of the cell. Its main component, peptidoglycan (PG), is essential for cell division and wall elongation. Penicillin-binding proteins (PBPs) catalyze the last steps of PG biosynthesis, namely the polymerization of glycan chains and the cross-linking of stem peptides, and can be either monofunctional or bifunctional. Their action is coordinated with that of other enzymes essential for cell-wall biosynthesis, such as lytic transglycosylases (LT). Here, we have studied SltB1, an LT from Pseudomonas aeruginosa, and identified that it forms a complex with PBP2, a monofunctional enzyme, which requires the presence of Ca(2+). In addition, we have solved the structure of SltB1 to a high resolution, and identified that it harbors an EF-hand like motif containing a Ca(2+) ion displaying bipyramidal coordination. These studies provide initial structural details that shed light on the interactions between the PG biosynthesis enzymes in P. aeruginosa.
authors.affiliation: Bacterial Pathogenesis Group, Institut de Biologie Structurale (IBS), Université Grenoble I, Grenoble, France.
authors.forename: Ioulia
authors.initials: I
authors.lastname: Nikolaidis
authors.forename: Thierry
authors.initials: T
authors.lastname: Izoré
authors.forename: Viviana
authors.initials: V
authors.lastname: Job
authors.forename: Nicole
authors.initials: N
authors.lastname: Thielens
authors.forename: Eefjan
authors.initials: E
authors.lastname: Breukink
authors.forename: Andréa
authors.initials: A
authors.lastname: Dessen
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002473:Cell Wall / Q000737:chemistry; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D016695:Glycosyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046915:Penicillin-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010457:Peptidoglycan / Q000096:biosynthesis*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D011550:Pseudomonas aeruginosa / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D046915:Penicillin-Binding Proteins; D010457:Peptidoglycan; D011994:Recombinant Proteins; D016695:Glycosyltransferases; D002118:Calcium