Influence of medium and long range interactions in protein folding

Protein structures are stabilized by both local and long range interactions . In this work, we analyze the residue-residue contacts and the role of med ium and long-range interactions in globular proteins belonging to different structural classes. The results show that while medium range interactions predominate in all-alpha class proteins, long-range interactions predominat e in an-beta class. Based on this, we analyze the performance of several st ructure prediction methods in different structural classes of globular prot eins and found that all the methods predict the secondary structures of all -alpha proteins more accurately than other classes. Also, we observed that the residues occurring in the range of 21-30 residues apart contributes mor e towards long-range contacts and about 85% of residues are involved in lon g-range contacts. Further, the preference of residue pairs to the folding a nd stability of globular proteins is discussed.