Results from protein mutagenesis and x-ray crystallographic studies of the
multidomain protein Vascular Cell Adhesion Molecule (VCAM) were used to des
ign cyclic octapeptides that retain the critical structural and binding ele
ments of the epitope of VCAM in the interaction with the integrin alpha(4)b
eta(1) (VLA-4). Changes in the activities of peptide analogues correlated w
ith the relative activities of protein mutants of VCAM, and predicted the p
roperties of two new mutants that bound alpha(4)beta(1) with improved affin
ity vs wild type protein. The nmr structures of two peptides revealed a hig
h degree of similarity to the structure of the VCAM binding epitope. These
results demonstrate that a compact binding epitope identified I ia protein
structure-function studies may be transferred to a synthetically accessible
small peptide with the key structure-activity relationships intact. (C) 19
98 John Wiley & Sons, Inc.