Département de chimie moléculaire

The design of short peptides with cyclic and linear components allows mimicking of the structure and reactivity of protein tetracysteinate zinc [Zn(Cys)4] sites of protein Hsp33. This is achieved with short peptides (about 20 amino acids) that are easy to synthesize. Moreover, their limited size allows rapid NMR structural characterization, which can scarcely be achieved with linear peptides or multihelix bundles. The differences between L2 and L3 peptides highlight the interest in this design over the use of linear peptides for the modeling of structural properties and reactivity. The comparison between L1 and L2 peptides shows that small changes in the structure and in the hydrogen bonding pattern of these complexes can influence their reactivity. The oxidn. of these [Zn(Cys)4] sites in conditions of severe H2O2 stress (100 $μ$M-5 mM) is very slow with half-life reaction times of several minutes, thus suggesting that H2O2 might not be the reactive oxygen species (ROS) actually responsible for the oxidn. in vivo. We are further exploring the reactivity of these promising models towards H2O2 and other ROS. [on SciFinder(R)]