Département de chimie moléculaire

RuII-TAP complexes have been shown to be very attractive compds. in the frame of developments of new anticancer drugs targeting the genetic material. This increasing interest originates from observations of covalent bond formations, triggered by photo-induced electron transfer (PET) between RuII-TAP complexes and guanine bases of DNA. This photoreaction has recently been extended to the tryptophan (Trp) amino acid for future applications involving peptides. Thus, a double photo-addn. of Trp residues of peptides on RuII complexes is demonstrated by mass spectrometry with some structural issues. Such bi-adduct formations offer the possibility of photocrosslinking two Trp-contg. biomols., which is investigated in this study. Thus, photocrosslinking between two complementary oligonucleotides (ODNs) derivatized by Trp-contg. tripeptides is demonstrated by PAGE in the presence of RuII-TAP complexes. Both PAGE and MS indicate that such photocrosslinkings arise from two reaction pathways: either via the double addn. of Trp residues on the Ru complex or from dimerization of Trp radicals. The competition between these two pathways depends on the exptl. conditions. Heterobridgings between guanine bases and tryptophan residues mediated by RuII-TAP complexes is also examd., opening the way to ODN-peptide photocrosslinkings. [on SciFinder(R)]