Influence of Medium and Long Range Interactions in (α/β)(8) Barrel Proteins.

The residue-residue contacts and the role of medium and long rangeinteractions in 36 (α/β)(8) barrel proteins have beenanalysed. The influence of long range contacts in the formation ofphysico-chemically similar clusters, and the preference of amino acidresidues towards long range contacts have also been studied. Theresults reveal a nearly uniform level of medium and long rangecontacts in most of the proteins. The residues Gln and Ala havehighest medium range contacts and the residue Pro has the lowestmedium range contacts. The residue Cys has the highest long rangecontact followed by other hydrophobic residues namely Val, Ile andLeu. In the physico-chemically similar clusters identified in theseproteins, 25-40 percent residues are influenced by long rangecontacts, and the residues Cys, Ile, Val and Met are the mostpreferred ones.