The present invention provides a cyclic peptide comprising the structure: ##STR00001## wherein X is selected from the group consisting of an amino acid, an amino acid analog, a peptidomimetic and a non-amide isostere, Z is selected from the group consisting of a synthetic amino acid and a biosynthetic amino acid, R is selected from the group consisting of oxygen, nitrogen, sulfur and carbon, n is 0 to 10 and y is 1 to 10. The present invention also provides a cyclic peptide comprising the amino acid sequence of NH.sub.2--X.sub.(n)-Z-X.sub.(y)--COOH and a cyclic bond between the Z residue and COOH other than a thioester bond, wherein X is selected from the group consisting of to an amino acid, an amino acid analog, a peptidomimetic and a non-amide isostere, Z is selected from the group consisting of a synthetic amino acid and a biosynthetic amino acid, n is 0 to 10 and y is 1 to 10. Methods of preparation including a cyclization protocol, and methods of use of the cyclic peptides of the invention are also disclosed.