SOLID-PHASE PEPTIDE-SYNTHESIS OF THE ALPHA-DOMAINS AND BETA-DOMAINS OF HUMAN LIVER METALLOTHIONEIN-2 AND THE METALLOTHIONEIN OF NEUROSPORA-CRASSA

The Cys-rich peptides corresponding to the α and β domains of human liver metallothionein 2 (MT-2) and the MT from Neurospora crassa (NcMT) have been prepared for the first time by solid-phase peptide synthesis and purified by HPLC. These synthetic peptides bind Cd(II), Ag(I), and Cu(I) in identical stoichiometries with the proteolytically derived domains from rat and rabbit liver MT and the natural NcMT. Absorption and CD features observed upon Cd(II) and Cu(I) binding to the synthetic peptides are qualitatively similar to those reported for the natural domains and NcMT. 113Cd NMR of the synthetic Cd4 α domain indicates that three of the metal ions are in environments identical with those in the whole protein and in the proteolytically derived α domain; the chemical shift of the fourth Cd(II), which is located near the junction with the β domain, indicates this metal ion is in a somewhat different environment than in the native protein. Thus, we have shown that it is possible to use solid-phase peptide synthesis to prepare MT. This demonstrates the successful use of solid-phase methods for peptides with high Cys content and now provides a methodology for the facile sequence modification of MT. © 1990, American Chemical Society. All rights reserved.