Complex lasso: new entangled motifs in proteins.

Area of Science:

• Structural biology
• Biophysics
• Computational biology

Background:

• Proteins with disulfide bridges exhibit complex three-dimensional structures.
• Understanding novel protein folding motifs is crucial for deciphering biological functions.

Purpose of the Study:

• To identify and characterize new entangled motifs in proteins, termed complex lassos.
• To classify the geometric properties of complex lassos and investigate their prevalence across different life forms.

Main Methods:

• Analysis of protein structures from the Protein Data Bank (PDB).
• Geometric classification of identified complex lasso motifs.
• Correlation of lasso occurrence with protein biological classification and potential functional implications.

Main Results:

• Complex lassos, a novel protein motif, were identified in proteins with disulfide bridges.
• Approximately 18% of disulfide-bonded proteins in a non-redundant PDB subset feature complex lassos.
• Six distinct geometric classes of lassos were defined, with one resembling DNA supercoiling.
• Lassos are significantly more common in proteins from viruses, plants, and fungi.

Conclusions:

• Complex lassos represent a significant structural feature in a subset of proteins.
• The prevalence and geometric diversity of lassos suggest important biological roles.
• Further research into lassos may reveal new applications in biomolecular engineering and understanding redox-sensitive proteins.