Importance of long-range interactions in protein folding

Long-range interactions play an active role in the stability of protein mol ecules. In this work, we have analyzed the importance of long-range interac tions in different structural classes of globular proteins in terms of resi due distances. We found that 85% of residues are involved in long-range con tacts. The residues occurring in the range of 4-10 residues apart contribut e more towards long-range contacts in all-alpha proteins while the range is 11-20 in all-beta proteins. The hydrophobic residues Cys, Ile and Val pref er the 11-20 range and all other residues prefer the 4-10 range. The residu es in all-beta proteins have an average of 3-8 long-range contacts whereas the residues in other classes have 1-3 long-range contacts. Furthermore, th e preference of residue pairs to the folding and stability will be discusse d. (C) 1999 Elsevier Science B.V. All rights reserved.