Exploiting a rational β-strand insertion strategy and disulfide locking to mechanically manipulate domain-swapped...

Area of Science:

• Protein structure and dynamics
• Biochemistry
• Structural biology

Background:

• Domain swapping (DS) is a mechanism where protein structural elements exchange, leading to altered oligomerization states.
• Previous research focused on hinge regions' role in protein oligomerization.
• The hinge loop in DS proteins connects distinct domains and is prone to significant structural changes.

Purpose of the Study:

• To investigate the manipulation of the hinge loop region in DS dimer proteins to generate altered protein structures.
• To explore methods for altering protein conformation without changing the oligomeric state.
• To understand how specific modifications to the hinge loop impact secondary and tertiary structures.

Main Methods:

• Systematic insertion of amino acids (odd vs. even numbers) into the hinge loop region of DS dimer proteins.
• Exploitation of the beta strand "zigzag" conformation principle to predict secondary structure alterations.
• Disulfide bond cross-linking strategy to reduce interdomain flexibility.

Main Results:

• Odd versus even amino acid insertions in the hinge loop predictably alter secondary structure.
• These modifications lead to predictable conformational changes in the overall 3D structure of DS dimers.
• Disulfide bond cross-linking successfully reduced interdomain flexibility in the modified DS dimers.

Conclusions:

• The hinge loop region of DS dimers can be precisely engineered to control protein structure and flexibility.
• Amino acid insertions in the hinge loop offer a method to fine-tune protein conformation without altering oligomerization.
• This study provides a strategy for designing novel protein structures with reduced flexibility.