Molecular Dynamics Study of the Cu2+ Binding-Induced “Structuring” of the N-Terminal Domain of Human Prion Protein

Histidine tracts in human transcription factors: insight into metal ion coordination ability

Consecutive histidine repeats are chosen both by nature and by molecular biologists due to their high affinity towards metal ions. Screening of the human genome showed that transcription factors are extremely rich in His tracts. In this work, we examine two of such His-rich regions from forkhead box and MAFA proteins-MB3 (contains 18 His) and MB6 (with 21 His residues), focusing on the affinity and binding modes of Cu2+ and Zn2+ towards the two His-rich regions. In the case of Zn2+ species, the availability of imidazole nitrogen donors enhances metal complex stability. Interestingly, an opposite tendency is observed for Cu2+ complexes at above physiological pH, in which amide nitrogens participate in binding.

Allosteric function and dysfunction of the prion protein

Transmissible spongiform encephalopathies (TSEs) are neurodegenerative diseases associated with progressive oligo- and multimerization of the prion protein (PrP(C)), its conformational conversion, aggregation and precipitation. We recently proposed that PrP(C) serves as a cell surface scaffold protein for a variety of signaling modules, the effects of which translate into wide-range functional consequences. Here we review evidence for allosteric functions of PrP(C), which constitute a common property of scaffold proteins. The available data suggest that allosteric effects among PrP(C) and its partners are involved in the assembly of multi-component signaling modules at the cell surface, impose upon both physiological and pathological conformational responses of PrP(C), and that allosteric dysfunction of PrP(C) has the potential to entail progressive signal corruption. These properties may be germane both to physiological roles of PrP(C), as well as to the pathogenesis of the TSEs and other degenerative/non-communicable diseases.

Prion proteins and copper ions. Biological and chemical controversies

The Prion protein (PrP(c)) involvement in some neurodegenerative diseases is well assessed although its "normal" biological role is not completely understood. It is known that PrP(C) can bind Cu(II) ions with high specificity but the order of magnitude of the corresponding affinity constant(s) is still highly debated. This perspective is an attempt to collect the current knowledge on these topics and to build up a bridge between the biological and the chemical points of view.

Insights into prion protein function from atomistic simulations

Computer simulations are a powerful tool for studies of biological systems. They have often been used to study prion protein (PrP), a protein responsible for neurodegenerative diseases, which include "mad cow disease" in cattle and Creutzfeldt-Jacob disease in humans. An important aspect of the prion protein is its interaction with copper ion, which is thought to be relevant for PrP's yet undetermined function and also potentially play a role in prion diseases. for studies of copper attachment to the prion protein, computer simulations have often been used to complement experimental data and to obtain binding structures of Cu-PrP complexes. This paper summarizes the results of recent ab initio calculations of copper-prion protein interactions focusing on the recently discovered concentration-dependent binding modes in the octarepeat region of this protein. In addition to determining the binding structures, computer simulations were also used to make predictions about PrP's function and the role of copper in prion diseases. The results demonstrate the predictive power and applicability of ab initio simulations for studies of metal-biomolecular complexes.