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Optimization of Synthetic Proteins: Identification of Interpositional Dependencies Indicating Structurally and/or Functionally Linked Residues
Published on: July 14, 2015
Native-state interconversion of a metamorphic protein requires global unfolding
Robert C Tyler1, Nathan J Murray, Francis C Peterson
1Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
Biochemistry
|July 23, 2011
Summary
Lymphotactin (Ltn), a metamorphic protein, rearranges its native state through large-scale unfolding, not a unique intermediate. This study reveals the temperature dependence of Ltn interconversion and unfolding kinetics.
Area of Science:
- Biochemistry
- Structural Biology
- Protein Dynamics
Background:
- Lymphotactin (Ltn) is a unique chemokine exhibiting structural heterogeneity, classifying it as a metamorphic protein.
- Previous research suggests distinct Ltn forms are essential for its function, yet the interconversion mechanism remains unclear.
Purpose of the Study:
- To investigate the temperature dependence of kinetic rates for Lymphotactin (Ltn) interconversion and unfolding.
- To determine the transition-state free energies associated with these processes.
- To elucidate the mechanism of Ltn native-state rearrangement.
Main Methods:
- Stopped-flow fluorescence spectroscopy was employed to monitor kinetic rates.
- Temperature dependence studies were conducted to analyze interconversion and unfolding.
- Thermodynamic parameters were derived and compared.
Main Results:
- Striking similarities were observed between the thermodynamic parameters of Ltn interconversion and protein unfolding.
- Kinetic rates for interconversion and unfolding were determined across a range of temperatures.
Conclusions:
- Lymphotactin (Ltn) native-state rearrangement occurs via a large-scale unfolding process.
- The findings suggest that Ltn does not proceed through a unique intermediate structure during rearrangement.
- This research provides new insights into the dynamics of metamorphic proteins.
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