Folding dynamics of phenylalanine hydroxylase depends on the enzyme’s metallation state: the native metal, iron, protects against aggregate intermediates

Metal complexes and metalloproteases: targeting conformational diseases

In recent years many metalloproteases (MPs) have been shown to play important roles in the development of various pathological conditions. Although most of the literature is focused on matrix MPs (MMPs), many other MPs have been demonstrated to be involved in the degradation of peptides or proteins whose accumulation and dyshomeostasis are considered as being responsible for the development of conformational diseases, i.e., diseases where non-native protein conformations lead to protein aggregation. It seems clear that, at least in principle, it must be possible to control the levels of many aggregation-prone proteins not only by reducing their production, but also by enhancing their catabolism. Metal complexes that can perform this function were designed and tested according to at least two different strategies: (i) intervening on the endogenous MPs by directly or indirectly modulating their activity; (ii) acting as artificial MPs, replacing or synergistically functioning with endogenous MPs. These two different bioinorganic approaches are widely represented in the current literature and the aim of this review is to rationally organize and discuss both of them so as to give a critical insight into these approaches and highlighting their limitations and future perspectives.

Monitoring the biomolecular interactions and the activity of Zn-containing enzymes involved in conformational diseases: experimental methods for therapeutic purposes

Zinc metalloproteases (ZnMPs) participate in diverse biological reactions, encompassing the synthesis and degradation of all the major metabolites in living organisms. In particular, ZnMPs have been recognized to play a very important role in controlling the concentration level of several peptides and/or proteins whose homeostasis has to be finely regulated for the correct physiology of cells. Dyshomeostasis of aggregation-prone proteins causes pathological conditions and the development of several different diseases. For this reason, in recent years, many analytical approaches have been applied for studying the interaction between ZnMPs and their substrates/inhibitors and how environmental factors can affect enzyme activities. In this scenario, nuclear magnetic resonance, X-ray diffraction, mass spectrometric (MS), and optical methods occupy a very important role in elucidating different aspects of the ZnMPs-substrates/inhibitors interaction, ranging from identification of cleavage sites to quantitation of kinetic parameters and inhibition constants. Here, an overview of all the main achievements in the application of different experimental approaches with special attention to MS methods to the investigation of ZnMPs-substrates/inhibitors interaction is given. A general MS experimental protocol which has been proved to be useful to study such interactions is also described.