Unique Substrate Specificity of SplE Serine Protease from Staphylococcus aureus

Structure. 2018 Apr 3;26(4):572-579.e4. doi: 10.1016/j.str.2018.02.008. Epub 2018 Mar 8.


Staphylococcus aureus is a dangerous human pathogen characterized by alarmingly increasing antibiotic resistance. Accumulating evidence suggests the role of Spl proteases in staphylococcal virulence. Spl proteases have restricted, non-overlapping substrate specificity, suggesting that they may constitute a first example of a proteolytic system in bacteria. SplA, SplB, and SplD were previously characterized in terms of substrate specificity and structural determinants thereof. Here we analyze the substrate specificity of SplE documenting its unique P1 preference among Spl proteases and, in fact, among all chymotrypsin-like (family S1) proteases characterized to date. This is interesting since our understanding of the general aspects of proteolysis is based on seminal studies of S1 family members. To better understand the molecular determinants of the unusual specificity of SplE, the crystal structure of the protein is determined here. Conclusions from structural analysis are evaluated by successful grafting of SplE specificity on the scaffold of SplB protease.

Keywords: SplE; Staphylococcus aureus; proteases; proteinase; structure; substrate specificity.

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
  • Cloning, Molecular
  • Crystallography, X-Ray
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • Kinetics
  • Models, Molecular
  • Mutation
  • Peptide Library
  • Peptides / chemistry*
  • Peptides / metabolism
  • Protein Binding
  • Protein Conformation, alpha-Helical
  • Protein Conformation, beta-Strand
  • Protein Interaction Domains and Motifs
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Sequence Alignment
  • Serine Proteases / chemistry*
  • Serine Proteases / genetics
  • Serine Proteases / metabolism
  • Staphylococcus aureus / chemistry*
  • Staphylococcus aureus / enzymology
  • Staphylococcus aureus / pathogenicity
  • Substrate Specificity
  • Virulence Factors / chemistry*
  • Virulence Factors / genetics
  • Virulence Factors / metabolism


  • Bacterial Proteins
  • Peptide Library
  • Peptides
  • Recombinant Proteins
  • Virulence Factors
  • Serine Proteases