Patent ID: 8324153

Claim:
An isolated peptide comprising a sequence from 14 to 21 amino acids in length, wherein two of the amino acids are unnatural amino acids having either R or S stereochemistry at the α-carbon; wherein the α-carbon of the unnatural amino acids comprises a methyl group and an olefinic group, where the two olefinic groups of the unnatural amino acids are on the same side of the α-helix and are joined to form a cross-link between the two unnatural amino acids; wherein the sequence of the peptide comprises (Q/A)(E/A/K)(V/W)(E/K)NW(M/A)TETLL(V/K)(QAE) (SEQ ID NO:18); wherein the two unnatural amino acids replace two of the amino acids at any positions four amino acids apart (i and i+4) or seven amino acids apart (i and i+7); and wherein the cross-link between the two unnatural amino acids is a C1-C10 alkyl, alkenyl, alkynyl, (R1-K—R1) n , each of which is substituted with a 0-6 R2, wherein R1 is an alkyl, alkenyl or alkynyl, K is O, S, SO, SO 2 , CO, CONR4, or R2 is a halo, C1-C10 alkyl, OR3, N(R3) 2 , SR3SOR3, SO 2 R3, CO 2 R3, R3, a fluorescent moiety or a radioisotope; R3 is H or a C1-C10 alkyl; R4 is H, alkyl or a therapeutic agent; and n is an integer from 1-4.