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Updated: May 21, 2026
Following Cell-fate in E. coli After Infection by Phage Lambda
Published on: October 14, 2011
Minimal requirements for inhibition of MraY by lysis protein E from bacteriophage ΦX174
Shiho Tanaka1, William M Clemons
1Division of Chemistry and Chemical Engineering, California Institute of Technology, M/C 114-96, Pasadena, CA 91125, USA.
Abstract:
The DNA phage ΦX174 encodes the integral membrane protein E whose expression leads to host cell lysis by inhibition of the peptidoglycan synthesis enzyme MraY. Here we use mutagenesis to characterize the molecular details of the E lysis mechanism. We find that a minimal 18-residue region with the modified wild-type sequences of the conserved transmembrane helix of E is sufficient to lyse host cells and that specific residues within and at the boundaries of this helix are important for activity. This suggests that positioning of the helix in the membrane is critical for interactions with MraY. We further characterize the interaction site of the transmembrane helix with MraY demonstrating E forms a stable complex with MraY. Triggering cell lysis by peptidoglycan synthesis inhibition is a traditional route for antimicrobial strategies. Understanding the mechanism of bacterial cell lysis by E will provide insights into new antimicrobial strategies using re-engineered E peptides.
Insights
Bacterial lysis protein E from phage ΦX174 uses its transmembrane helix to inhibit peptidoglycan synthesis by binding MraY. This mechanism provides a foundation for developing novel antimicrobial peptides.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- The DNA phage ΦX174 produces integral membrane protein E.
- Protein E inhibits the peptidoglycan synthesis enzyme MraY, leading to host cell lysis.
- Peptidoglycan synthesis inhibition is a known antimicrobial strategy.
Purpose of the Study:
- To elucidate the molecular mechanism of protein E-mediated bacterial cell lysis.
- To identify the key regions and residues of protein E involved in MraY inhibition.
- To characterize the interaction between protein E and MraY.
Main Methods:
- Site-directed mutagenesis of the conserved transmembrane helix of protein E.
- Analysis of the lytic activity of mutant protein E variants.
- Characterization of the complex formed between protein E and MraY.
Main Results:
- A minimal 18-residue region within the transmembrane helix of protein E is sufficient for host cell lysis.
- Specific residues within and at the boundaries of this helix are critical for lytic activity.
- Protein E forms a stable complex with MraY, indicating a direct interaction.
Conclusions:
- The precise positioning of the transmembrane helix of protein E within the membrane is crucial for its interaction with MraY.
- Understanding the E-MraY interaction mechanism offers insights into developing new antimicrobial agents.
- Re-engineered E peptides could serve as a basis for novel antimicrobial strategies targeting bacterial cell wall synthesis.
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