Computational design of a self-assembling symmetrical β-propeller protein

Area of Science:

• Structural biology
• Computational protein design
• Biochemistry

Background:

• The modular nature of protein families like beta-propeller proteins suggests evolutionary roles for gene duplication.
• Previous efforts to engineer perfectly symmetrical propeller proteins have been unsuccessful.

Purpose of the Study:

• To develop a rapid computational method for designing highly symmetrical beta-propeller proteins.
• To computationally design and experimentally validate a de novo sixfold symmetrical beta-propeller protein.

Main Methods:

• A novel computational approach was employed for protein design.
• X-ray crystallography was used for experimental structure validation.
• Proteins with varying numbers of tandem blades (2-10) were expressed and purified.

Main Results:

• A de novo sixfold symmetrical beta-propeller protein with 42-residue blades was successfully designed and validated.
• Tandem blade arrangements (2-3 blades) reconstituted the stable sixfold symmetrical architecture.
• Proteins with more blades self-assembled into monodisperse complexes up to 42 blades (180 kDa) following simple symmetry rules.

Conclusions:

• The developed computational method is effective for designing symmetrical protein structures.
• The findings support the duplication and fusion theory in protein evolution.
• This approach facilitates the creation of protein-based nano-building blocks with controlled symmetry.