Solution structure of a peptide derived from the β subunit of LFA-1

Cell-adhesion molecules are critical for immune response. It is well known that the inhibition of adhesion is very effective in inimuno-therapy and that the peptides derived from leukocyte function associated antigen (LFA-1) and intercellular adhesion molecule (ICAM-1) modulate cell-adhesion interaction. The three-dimensional structure of acyclic peptide, Cyclo(1,12)Pen(1)-Asp(2)-Leu(3)-Ser(4)-Tyr(5)-Ser(6)-Leu(7)-Asp(8)-Asp(9)-Leu(10)-Arg(11)-Cys(12) (cLBEL) derived from the beta subunit of LFA-1 which is known to modulate homotypic T-cell-adhesion process has been studied using NMR, CD and molecular dynamics (MD) simulation. The peptide exhibits two possible conformations in solution. Structure I has a conformation with two consecutive beta-turns involving residues Tyr(5)-Ser(6)-Leu(7)-Asp(8) and Asp(9)-Leu(10)-Arg(11)-Cys(12). Structure II has a beta-turn at Tyr(5)-Ser(6)-Leu(7)-Asp(8) and forms a beta-hairpin type of conformation. (C) 2003 Elsevier Inc. All rights reserved.