Foldable subunits of helix protein

Area of Science:

• Protein folding dynamics
• Structural biology
• Computational biophysics

Background:

• Understanding protein folding is crucial for evolutionary studies and de novo protein design.
• The C-terminal domain of Ku86 (120 amino acids) is a six-helix protein.
• Quasi-two-fold symmetry in protein sequence and structure can inform folding mechanisms.

Purpose of the Study:

• To investigate the folding behavior of the C-terminal domain of Ku86.
• To determine if the protein can be divided into independently foldable subunits.
• To explore potential building motifs for de novo protein design.

Main Methods:

• Simulated protein folding using a united-residue model.
• Analyzed folding behaviors, structural topology, and sequence repetition.
• Examined the independent folding of the two halves (amino acids 1-60 and 61-120).

Main Results:

• The C-terminal domain of Ku86 exhibits characteristics of two-fold quasi-repetition.
• Simulations showed that the two halves (1-60 and 61-120) can fold into native conformations independently.
• The folding patterns of these halves are comparable to those of three-helix bundles.

Conclusions:

• The C-terminal domain of Ku86 may be composed of two distinct, independently foldable halves.
• This finding supports the concept of modularity in protein structure and folding.
• Identified potential subunits for future de novo protein design strategies.