A de novo peptide hexamer with a mutable channel

Area of Science:

• Protein engineering
• Structural biology
• Biotechnology

Background:

• Designing novel protein structures beyond natural ones is challenging.
• New protein scaffolds are valuable for biotechnology and synthetic biology.
• Understanding protein structure-function relationships is key.

Purpose of the Study:

• To design, characterize, and determine the X-ray crystal structure of a de novo coiled-coil protein.
• To investigate the properties of a hydrophobic channel within the designed protein.
• To explore the functional implications of mutations within the channel.

Main Methods:

• De novo protein sequence design.
• X-ray crystallography for structure determination.
• Mutagenesis studies to alter channel properties.

Main Results:

• A stable, parallel, six-helix bundle protein was successfully designed.
• The protein features a 6-Å hydrophobic channel permeable to water.
• Mutations introduced polar residues, subdividing the channel and organizing solvent.
• A stable heterohexameric mutant protein ((Asp-His)3) was created.

Conclusions:

• The designed coiled-coil protein represents a new structural scaffold.
• The channel's properties can be modulated by amino acid substitutions.
• These findings provide a foundation for engineering novel protein functions.