Synthesis and characterization of the human CC chemokine HCC-2

Human CC chemokine 2 (HCC-2) is a novel member of the chemokine peptide fam ily that induces chemotaxis of monocytes, T lymphocytes and eosinophils via activation of the CCR-1 and CCR-3 receptors. Fmoc chemistry was optimized and used to synthesize the biologically active 66-residue peptide HCC-2-(48 -113). Introduction of the three disulfide bonds was achieved by oxidative folding in the presence of the redox system cysteine/cystine. Alternatively , a semiselective approach utilizing a mixed Acm/Trt protection scheme for disulfide formation was applied. It was found that, without participation o f the two HCC-2-specific cysteine residues in positions 64 and 104, the two typical chemokine disulfides are formed predominantly during oxidative fol ding. In addition, the mutant [Ala64,104]HCC-2-(48-113) lacking the third d isulfide bond that discriminates HCC-2 from most other chemokines was synth esized. For disulfide bond formation, oxidative folding was compared with t he use of Acm/Trt protection. HCC-2-(48-113) and the mutant [Ala64,104]HCC- 2-(48-113) were further analyzed by CD and one-dimensional H-1 NMR-spectros copy. Both peptides adopt a similar stable secondary and tertiary structure in solution.