Importance of long-range interactions in (α/β)8 barrel fold

Protein structures are stabilized by both local and long-range interactions. In this work, we analyzed the importance of long-range interactions in (α/β)₈ barrel proteins in terms of residue distances. We found that the residues occurring in the range of 21–30 residues apart contribute more toward long-range contacts. Indeed, about 50% of successive strands in these proteins are found to occur at a sequential distance of 21–30 residues. The aromatic amino acid residues Phe, Trp, and Tyr prefer the 4–10 range and all other residues prefer the 21–30 range. Hydrophobic-hydrophobic resideu pairs are the most preferred ones for long-range interactions and they may play a key role in the folding and stabilization of (α/β)₈ barrel proteins.