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Does macromolecular crowding compatible with enzyme stem bromelain structure and stability?
Kavya Bhakuni1, Pannuru Venkatesu1
1Department of Chemistry, University of Delhi, Delhi 110 007, India.
International Journal of Biological Macromolecules
|March 19, 2019
Summary
Macromolecular crowding affects stem bromelain (BM) structure and activity. Dextran (D70) stabilizes BM, while polyethylene glycol (P12, P20) alters its structure, with soft interactions dominating.
Area of Science:
- Biochemistry
- Protein Science
- Biophysical Chemistry
Background:
- Understanding protein behavior in crowded biological environments is crucial.
- Macromolecular crowding significantly influences protein structure, dynamics, and function.
- Stem bromelain (BM) has industrial applications, necessitating study of its behavior under crowding conditions.
Purpose of the Study:
- To investigate the impact of macromolecular crowding on stem bromelain (BM) structure and activity.
- To evaluate the effects of dextran (D70) and polyethylene glycol (P12, P20) as crowding agents on BM.
- To elucidate the molecular interactions governing crowder effects on BM.
Main Methods:
- Spectroscopic techniques including absorption, circular dichroism, and fluorescence.
- Enzyme activity assays to quantify functional changes.
- Molecular docking studies to investigate molecular-level interactions.
Main Results:
- Crowding agents alter BM structure and activity compared to dilute solutions.
- Dextran (D70) acts as a thermal stabilizing agent for BM.
- Polyethylene glycol (P12) shows moderate stabilization, while P20 destabilizes BM structure.
- Overall, crowders exhibited a destabilizing and deactivating effect on the enzyme.
Conclusions:
- Macromolecular crowding significantly impacts stem bromelain's structural integrity and enzymatic activity.
- The nature of the crowder (e.g., D70, P12, P20) dictates its stabilizing or destabilizing effect.
- Soft interactions play a dominant role in the observed effects of macromolecular crowding on BM, overriding excluded volume effects.
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