Exploring the copper binding ability of Mets7 hCtr-1 protein domain and His7 derivative: An insight in Michael addition catalysis.

Mets7 is a methionine-rich motif present in hCtr-1 transporter that is involved in copper cellular trafficking. Its ability to bind Cu(I) was recently exploited to develop metallopeptide catalysts for Henry condensation. Here, the catalytic activity of Mets7-Cu(I) complex in Michael addition reactions has been evaluated. Furthermore, His7 peptide, in which Met residues have been substituted with His ones, was also prepared. This substitution allowed His7 to coordinate Cu (II), with the obtainment of a stable turn conformation as evicted by CD experiments. His7-Cu (II) proved also to be a better catalyst than Mets7-Cu(I) in the addition reaction. In particular, when the substrate was the (E)-1-phenyl-3-(pyridin-2-yl)prop-2-en-1-one, a conversion of 71% and a significative 58% of e.e. was observed.