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Local structural preferences in the alpha-lactalbumin molten globule
1Howard Hughes Medical Institute, Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Nine Cambridge Center 02142.
Biochemistry
|March 14, 1995
Summary
Molten globules, key protein folding intermediates, show specific structural preferences. The helical domain of alpha-lactalbumin
Area of Science:
- Protein folding dynamics
- Biophysical chemistry
- Structural biology
Background:
- Molten globules are proposed general intermediates in protein folding.
- Detailed molten globule structure remains elusive.
- Alpha-lactalbumin (alpha-LA) helical domain molten globule exhibits native-like backbone topology.
Purpose of the Study:
- To investigate local structural preferences within the alpha-LA molten globule.
- To analyze native and nonnative single disulfide bond variants.
- To understand the role of specific regions in molten globule stability.
Main Methods:
- Circular dichroism spectroscopy.
- Equilibrium constant determination for disulfide bond formation.
- Analysis of native and nonnative disulfide bond variants.
Main Results:
- The region around the 28-111 disulfide bond shows a strong preference for native-like structure.
- Formation of other native or nonnative disulfide bonds is less favorable.
- Molten globules possess regions with specific native-like structural tendencies.
Conclusions:
- Molten globules exhibit varying degrees of native-like structural specificity.
- The core region around the 28-111 disulfide bond is crucial for stabilizing the alpha-LA molten globule intermediate.
- This region plays a significant role in the overall protein folding pathway.