Calcium-dependent complex formation between PBP2 and lytic transglycosylase SltB1 of Pseudomonas aeruginosa

Microb Drug Resist. 2012 Jun;18(3):298-305. doi: 10.1089/mdr.2012.0006. Epub 2012 Mar 20.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Binding Sites
  • Calcium / metabolism*
  • Cell Wall / chemistry
  • Cloning, Molecular
  • Crystallography, X-Ray
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Glycosyltransferases / chemistry*
  • Glycosyltransferases / genetics
  • Glycosyltransferases / metabolism
  • Models, Molecular
  • Molecular Sequence Data
  • Penicillin-Binding Proteins / chemistry*
  • Penicillin-Binding Proteins / genetics
  • Penicillin-Binding Proteins / metabolism
  • Peptidoglycan / biosynthesis*
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Pseudomonas aeruginosa / chemistry*
  • Pseudomonas aeruginosa / genetics
  • Pseudomonas aeruginosa / metabolism
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Sequence Alignment


  • Bacterial Proteins
  • Penicillin-Binding Proteins
  • Peptidoglycan
  • Recombinant Proteins
  • Glycosyltransferases
  • Calcium