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X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
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Elucidating the pH-Dependent Structural Transition of T7 Bacteriophage Endolysin
Meenakshi Sharma, Dinesh Kumar1, Krishna Mohan Poluri
1Centre of Biomedical Research, SGPGIMS , Lucknow 226014, Uttar Pradesh, India.
Biochemistry
|August 12, 2016
Summary
Bacteriophage T7 lysozyme (T7L) undergoes a reversible structural change below pH 6, revealing exposed hydrophobic pockets. This pH-dependent dynamics, driven by histidine residues, is crucial for designing effective enzybiotic antimicrobials.
Area of Science:
- Biochemistry
- Structural Biology
- Microbiology
Background:
- Bacteriophage endolysins, like T7 lysozyme (T7L), are peptidoglycan hydrolases with potential as enzybiotics against bacterial infections.
- T7L lyses Gram-negative bacteria by targeting the peptidoglycan layer, but the molecular basis for its pH-dependent activity remains unclear.
Purpose of the Study:
- To investigate the pH-induced structural, stability, and activity changes in T7 bacteriophage endolysin (T7L).
- To elucidate the molecular mechanisms underlying T7L's pH-dependent conformational dynamics.
Main Methods:
- Utilized biophysical techniques including protein nuclear magnetic resonance (NMR) spectroscopy.
- Performed NMR relaxation measurements and structural analysis.
Main Results:
- Identified a reversible structural transition in T7L below pH 6, leading to a stable, partially denatured conformation at pH 3 with exposed hydrophobic pockets.
- NMR data revealed T7L's dynamic native state and highlighted a network of histidine residues critical for pH-dependent conformational changes.
Conclusions:
- The study clarifies the structural and dynamic basis of T7L's pH-dependent activity.
- Findings provide insights for designing engineered endolysins as broad-spectrum antimicrobial agents against drug-resistant pathogens.
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