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Optimized Negative Staining: a High-throughput Protocol for Examining Small and Asymmetric Protein Structure by Electron Microscopy
Published on: August 15, 2014
Structural basis for thermal stability of human low-density lipoprotein
Shobini Jayaraman1, Donald Gantz, Olga Gursky
1Department of Physiology and Biophysics, W329, Boston University School of Medicine, 715 Albany Street, Boston, Massachusetts 02118, USA.
Biochemistry
|March 9, 2005
Summary
The thermal stability of human low-density lipoprotein (LDL) involves complex structural changes, not global unfolding. Kinetic barriers protect LDL
Area of Science:
- Biochemistry
- Structural Biology
- Lipid Metabolism
Background:
- Low-density lipoprotein (LDL) is the primary plasma carrier of cholesterol.
- Understanding LDL's structural integrity is crucial for cardiovascular health research.
Purpose of the Study:
- To investigate the thermal stability and disruption mechanisms of human LDL.
- To correlate structural changes with calorimetric and spectroscopic data.
Main Methods:
- Differential scanning calorimetry
- Circular dichroism (CD) spectroscopy (UV-Vis, near-UV)
- Fluorescence spectroscopy
- Turbidity measurements
- Electron microscopy
Main Results:
- Thermal disruption causes irreversible changes in LDL morphology and apoB conformation, without global unfolding.
- Heating induces LDL conversion, partial apoB dissociation, and lipid droplet fusion.
- A high-temperature calorimetric peak corresponds to fused lipid droplets resembling atherosclerotic deposits.
- LDL fusion exhibits strong concentration dependence and high activation energy, indicating kinetic barriers.
Conclusions:
- LDL's thermal stability is governed by kinetic barriers, not just unfolding.
- These barriers may maintain the structural integrity of LDL subclasses in vivo.
- The observed lipid droplets mimic early atherosclerotic extracellular lipid deposits.
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