π-π Interactions in structural stability: role in RNA binding proteins

Area of Science:

• Biochemistry
• Structural Biology
• Molecular Biology

Background:

• RNA binding proteins are essential for numerous biological processes.
• Aromatic amino acid residues, including phenylalanine (Phe), tyrosine (Tyr), and tryptophan (Trp), play critical roles in protein function.
• Understanding the interactions involving these residues is key to deciphering protein behavior.

Purpose of the Study:

• To analyze the role and prevalence of π-π interactions involving aromatic residues in RNA binding proteins.
• To investigate the types and significance of these interactions for protein structure and stability.

Main Methods:

• Analysis of residue composition in a dataset of RNA binding proteins.
• Identification and quantification of aromatic residues (Phe, Tyr, Trp).
• Mapping and classification of π-π interactions, distinguishing between side chain-side chain and other types.

Main Results:

• A total of 3,396 aromatic residues were identified, with Phe, Tyr, and Trp comprising 1,547, 1,241, and 608, respectively.
• A significant majority of these aromatic residues (945 Phe, 634 Tyr, 356 Trp) are involved in π-π interactions.
• Side chain-to-side chain π-π interactions are the most common type, stabilizing protein cores.
• π-π interacting residues exhibit evolutionary conservation and possess higher long-range contacts, contributing to global conformational stability.

Conclusions:

• π-π interactions are a dominant force among aromatic residues in RNA binding proteins.
• These interactions are critical for maintaining the structural integrity and stability of RNA binding proteins.
• The evolutionary conservation of these interacting residues underscores their functional importance.