RESUMEN
Recently, we reported on a series of aminomethylene-phosphonate (AMP) analogues, bearing one or two heterocyclic groups on the aminomethylene moiety, as promising Zn(II) chelators. Given the strong Zn(II) binding properties of these compounds, they may find useful applications in metal chelation therapy. With a goal of inhibiting the devastating oxidative damage caused by prion protein in prion diseases, we explored the most promising ligand, {bis[(1H-imidazol-4-yl)methyl]amino}methylphosphonic acid, AMP-(Im)2, 4, as an inhibitor of the oxidative reactivity associated with the Cu(II) complex of prion peptide fragment 84-114. Specifically, we first characterized the Cu(II) complex with AMP-(Im)2 by ultraviolet-visible spectroscopy and electrochemical measurements that indicated the high chemical and electrochemical stability of the complex. Potentiometric pH titration provided evidence of the formation of a stable 1:1 [Cu(II)-AMP-(Im)2]+ complex (ML), with successive binding of a second AMP-(Im)2 molecule yielding ML2 complex [Cu(II)-(AMP-(Im)2)2]+ (log K' = 15.55), and log ß' = 19.84 for ML2 complex. The CuN3O1 ML complex was demonstrated by X-ray crystallography, indicating the thermodynamically stable square pyramidal complex. Chelation of Cu(II) by 4 significantly reduced the oxidation potential of the former. CuCl2 and the 1:2 Cu:AMP-(Im)2 complex showed one-electron redox of Cu(II)/Cu(I) at 0.13 and -0.35 V, respectively. Indeed, 4 was found to be a potent antioxidant that at a 1:1:1 AMP-(Im)2:Cu(II)-PrP84-114 molar ratio almost totally inhibited the oxidation reaction of 4-methylcatechol. Circular dichroism data suggest that this antioxidant activity is due to formation of a ternary, redox inactive Cu(II)-Prp84-114-[AMP-(Im)2] complex. Future studies in prion disease animal models are warranted to assess the potential of 4 to inhibit the devastating oxidative damage caused by PrP.
Asunto(s)
Cobre/química , Isoxazoles/química , Priones/química , Tetrazoles/química , Modelos Moleculares , Oxidación-Reducción , Conformación ProteicaRESUMEN
Studies of traditional healers in various cultures describe their initiation into the healing profession as a climax that constructs their professional and personal identity. Literature emphasizes the healers' intense association with the culture in which they work, as reflected in the initiation narratives that healers in various cultures recount. In this article we reveal unique initiation stories and identity formation from Palestinian nonconventional healers in Israel who described a cross-cultural journey: After studying healing traditions of foreign cultures and on returning to their own cultural environment, they developed a unique and complex combination of healing values and traditions. We examine the stories of these healers, whose personal and professional identities are affected by cultural, political, and social contexts. We note the blending of healing traditions and practices, and the changes in identity, assessing them against cultural processes that many Palestinians in Israel have been undergoing over the past few decades.