Related Experiment Videos
Modulation of dimerization, binding, stability, and folding by mutation of the neurophysin subunit interface
S Eubanks1, T L Nguyen, D Peyton
1Department of Biochemistry, The Joan and Sanford I. Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10021, USA.
Biochemistry
|July 13, 2000
Summary
Porcine neurophysin folds efficiently without ligands due to increased dimerization, unlike bovine neurophysin. Specific mutations at the subunit interface in porcine neurophysin explain these functional differences.
Area of Science:
- Protein structure and function
- Biochemistry
- Molecular biology
Background:
- Bovine neurophysins are models for neurophysin behavior but require ligand stabilization for proper folding.
- Unliganded porcine neurophysin exhibits significantly higher dimerization than bovine neurophysin.
Purpose of the Study:
- To investigate the molecular basis for functional differences between bovine and porcine neurophysins.
- To identify specific mutations responsible for enhanced dimerization and stability in porcine neurophysin.
Main Methods:
- Site-specific mutagenesis of bovine neurophysin.
- Expression of mutant proteins in Escherichia coli.
- Analysis of dimerization constants and peptide-binding affinities.
Main Results:
- Two mutations in the porcine neurophysin subunit interface (His80Arg, Glu81Phe) account for functional differences.
- His80Arg mutation alone had minor effects on dimerization, while other substitutions reduced it.
- His-80 substitutions altered binding affinity and specificity independently of dimerization effects.
Conclusions:
- The carboxyl domain of the subunit interface is crucial for modulating neurophysin properties.
- Ligand-induced conformational changes in this region contribute significantly to binding thermodynamics.
- Generated self-folding and monomeric mutants offer potential for future research.