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A four amino acid peptide containing the β-turn template dPro-Pro in the middle and two cysteines (Cys) in the terminal positions (CdPPC) has been synthesized and its mercury(II) coordination properties studied using different spectroscopic methods. The UV-vis, CD, (199m)Hg PAC, and Raman spectroscopic studies indicate the binding of Hg(II) to the two Cys, forming the dithiolatemercury(II) complex Hg(CdPPC). Electrospray ionization mass spectrometry corroborates the 1:1 complex formation. A log K = 40.0 was determined for the formation constant of the Hg(CdPPC) complex using competition potentiometric studies. Replacement of the dPro-Pro motif by a Pro-Pro unit generated a peptide (CPPC) capable of forming a similar species [Hg(CPPC)] but showing a lower affinity for Hg(II) (at least 3-3.5 orders of magnitude lower). The introduction of the dPro-Pro motif is crucial to induce the folding of the CdPPC peptide into a β-turn, preorganizing the two Cys for mercury(II) coordination. While the simple dPro-Pro unit mimics the overall preorganization achieved by the protein scaffold in metalloproteins containing the conserved metal ion chelation unit CXXC, the high thiophilicity of this metal stabilizes the final complex in a wide pH range (1.1-10). Using computational modeling, the structures of two conformers for Hg(CdPPC) have been optimized that differ mainly in the orientation of the plane containing S-Hg-S with respect to the anchoring C atoms.

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This paper assesses the implementation and use of sustainability indicators (SI) in local governance contexts in Portugal. The need to analyse the development of local SI is considered critical, given the lack of research on the understanding of how, when and by whom SI are implemented and used, particularly in the Portuguese local governance M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPTcontext. The first aim of this article is to map experiences of SI in Portugal by assessing how many local councils developed indicator systems and when, and the major driving forces and general features of those systems. The second aim is to analyse and compare 7 case studies, in further detail, to explore the governance factors that influence indicator success and how indicators are used within local contexts. Two particular conceptual frameworks were applied to structure research and analysis. Based on a national survey and case study methodology, findings reveal that local SI in Portugal are still in early stages of development. Where SI have been designed earlier, there has been a lack of political commitment and vision, and a need to overcome local government malfunctioning more than the complex obstacles of sustainable development governance. Applying both conceptual frameworks enabled to present critical lessons on the relationship among governance factors and types of uses when implementing SI in Portugal and to suggest the value of this integrated analysis for other governance contexts.