Abstract
The molecular target for the bacteriolytic E protein from bacteriophage X174, responsible for host cell lysis, is known to be the enzyme phospho-MurNAc-pentapeptide translocase (MraY), an integral membrane protein involved in bacterial cell wall peptidoglycan biosynthesis, with an essential role being played by peptidyl-prolyl isomerase SlyD. A synthetic 37 aa peptide E(pep), containing the N-terminal transmembrane alpha-helix of E, was found to be bacteriolytic against Bacillus licheniformis, and inhibited membrane-bound MraY. The solution conformation of E(pep) was found by circular dichroism (CD) spectroscopy to be 100 % alpha-helical. No change in the CD spectrum was observed upon addition of purified Escherichia coli SlyD, implying that SlyD does not catalyse prolyl isomerization upon E. However, E(pep) was found to be a potent inhibitor of SlyD-catalysed peptidyl-prolyl isomerization (IC(50) 0.15 microM), implying a strong interaction between E and SlyD. E(pep) was found to inhibit E. coli MraY activity when assayed in membranes (IC(50) 0.8 microM); however, no inhibition of solubilized MraY was observed, unlike nucleoside natural product inhibitor tunicamycin. These results imply that the interaction of E with MraY is not at the MraY active site, and suggest that a protein-protein interaction is formed between E and MraY at a site within the transmembrane region.
Original language | English |
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Pages (from-to) | 2959-2967 |
Number of pages | 9 |
Journal | BMC Microbiology |
Volume | 152 |
Issue number | Pt 10 |
Early online date | 1 Oct 2006 |
DOIs | |
Publication status | Published - Oct 2006 |
Externally published | Yes |
Keywords
- Anti-Bacterial Agents
- Bacillus
- Bacterial Proteins
- Bacteriolysis
- Circular Dichroism
- Escherichia coli Proteins
- Models, Biological
- Peptides
- Peptidylprolyl Isomerase
- Protein Binding
- Protein Interaction Mapping
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Transferases
- Viral Proteins
- Journal Article
- Research Support, Non-U.S. Gov't