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pH driven conformational dynamics and dimer-to-monomer transition in DLC8.
P M Krishna Mohan1, Maneesha Barve, Amarnath Chatterjee
1Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India.
Protein Science : a Publication of the Protein Society
|December 31, 2005
Summary
Dynein light chain protein changes structure with pH. Lowering pH causes dynamics and loosening, eventually leading to dimer dissociation, impacting cargo binding and transport.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Dynein light chain protein functions as a homodimer in cytoplasmic motor assemblies.
- Dimerization is crucial for binding target proteins and cargo trafficking.
- The protein exists as a monomer below pH 4.5, losing its binding ability.
Purpose of the Study:
- To investigate the pH-induced structural and motional changes in dynein light chain protein.
- To understand the relationship between pH, protein dynamics, and cargo binding.
- To elucidate the mechanism of dimer dissociation at low pH.
Main Methods:
- Utilized line broadening and 15N transverse relaxation measurements.
- Analyzed pH-dependent structural and motional transitions.
- Investigated changes in histidine protonation and their effect on protein conformation.
Main Results:
- At pH 7-5, decreasing pH increases conformational dynamics in the dimeric protein due to histidine protonation.
- Enhanced dynamics lead to partial loosening of the dimeric structure.
- Below pH 5, charge repulsions, loss of hydrophobic interactions, and H-bond destabilization cause further loosening and eventual dimer dissociation.
Conclusions:
- pH-induced conformational changes in dynein light chain protein affect its structure and dynamics.
- Variations in cellular pH can alter cargo binding efficacy, impacting intracellular transport.
- The study provides insights into the regulation of dynein motor function by pH.