Favorable scaffolds: proteins with different sequence, structure and function may associate in similar ways

Area of Science:

• Structural biology
• Biochemistry
• Bioinformatics

Background:

• Proteins with similar structures often share similar functions.
• The relationship between structural similarity and functional similarity extends to protein-protein interfaces.
• Understanding protein-protein interactions is crucial for various biological processes.

Purpose of the Study:

• To investigate whether similar protein interfaces always originate from globally similar protein structures and functions.
• To analyze the characteristics of protein interface clusters with varying degrees of global structural and functional similarity.
• To explore the implications of these findings for protein recognition, cellular networks, and drug design.

Main Methods:

• Utilized a non-redundant two-chain protein-protein interface dataset.
• Clustered the dataset into 103 distinct groups based on interface similarity.
• Compared interface clusters based on global chain structures, functions, and interface properties (packing, planarity, buried surface area, complementarity, hydrogen bonds).

Main Results:

• Identified clusters where similar interfaces were associated with different global protein structures and functions (Type II).
• Contrasted Type II clusters with Type I clusters (similar interfaces, structures, and functions).
• Type I interfaces exhibited better packing, were less planar, had larger buried surface areas, greater complementarity, and more hydrogen bonds than Type II.

Conclusions:

• Different protein folds can assemble to create similar local interface motifs.
• The principle of structural similarity correlating with functional similarity is not absolute for protein interfaces.
• These findings offer valuable insights into protein-protein recognition, cellular networks, and potential drug design strategies.