Structure and lytic activity of a Bacillus anthracis prophage endolysin

J Biol Chem. 2005 Oct 21;280(42):35433-9. doi: 10.1074/jbc.M502723200. Epub 2005 Aug 15.


We report a structural and functional analysis of the lambda prophage Ba02 endolysin (PlyL) encoded by the Bacillus anthracis genome. We show that PlyL comprises two autonomously folded domains, an N-terminal catalytic domain and a C-terminal cell wall-binding domain. We determined the crystal structure of the catalytic domain; its three-dimensional fold is related to that of the cell wall amidase, T7 lysozyme, and contains a conserved zinc coordination site and other components of the catalytic machinery. We demonstrate that PlyL is an N-acetylmuramoyl-L-alanine amidase that cleaves the cell wall of several Bacillus species when applied exogenously. We show, unexpectedly, that the catalytic domain of PlyL cleaves more efficiently than the full-length protein, except in the case of Bacillus cereus, and using GFP-tagged cell wall-binding domain, we detected strong binding of the cell wall-binding domain to B. cereus but not to other species tested. We further show that a related endolysin (Ply21) from the B. cereus phage, TP21, shows a similar pattern of behavior. To explain these data, and the species specificity of PlyL, we propose that the C-terminal domain inhibits the activity of the catalytic domain through intramolecular interactions that are relieved upon binding of the C-terminal domain to the cell wall. Furthermore, our data show that (when applied exogenously) targeting of the enzyme to the cell wall is not a prerequisite of its lytic activity, which is inherently high. These results may have broad implications for the design of endolysins as therapeutic agents.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amidohydrolases / chemistry
  • Amidohydrolases / physiology*
  • Amino Acid Sequence
  • Bacillus anthracis / metabolism*
  • Bacterial Proteins
  • Binding Sites
  • Catalytic Domain
  • Cell Wall / metabolism
  • Cloning, Molecular
  • Endopeptidases / chemistry*
  • Genome, Bacterial
  • Models, Biological
  • Models, Molecular
  • Models, Statistical
  • Molecular Sequence Data
  • N-Acetylmuramoyl-L-alanine Amidase / chemistry
  • Peptidoglycan / chemistry
  • Prophages / chemistry*
  • Prophages / metabolism*
  • Protein Binding
  • Protein Conformation
  • Protein Folding
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid
  • Species Specificity
  • Time Factors
  • Zinc / chemistry


  • Bacterial Proteins
  • Peptidoglycan
  • Endopeptidases
  • endolysin
  • Amidohydrolases
  • PlyL protein, Bacillus anthracis
  • N-Acetylmuramoyl-L-alanine Amidase
  • amidase
  • Zinc

Associated data

  • PDB/1YB0