Nitric oxide selectively releases metals from theN‐terminal domain of metallothioneins: potential role at inflammatory sites

Abstract

SPECIFIC AIMSWe examined the structural consequences of the release of metal ions from the small, cysteine-rich, metal binding protein metallothionein (MT) brought about by the interaction with nitric oxide (NO). Homonuclear (1H) as well as heteronuclear (113Cd) NMR spectroscopy was used to characterize the structural changes associated with this interaction of potential physiological significance.PRINCIPAL FINDINGS1. Nitric oxide selectively releases metals from the amino-terminal domain of metallothioneinsTo monitor the structural changes upon the interaction of nitric oxide with metallothionein, a 1 mM mouse [Cd7]-metallothionein-1 sample was titrated with an NO donor (DEA/NO) and monitored by NMR spectroscopy. The amount of DEA/NO added at each increment corresponded to 0.5 mM of NO after complete release from its donor. After the first addition, it became obvious that the presence of NO leads to the selective reduction of 1H-NMR signal intensities from the amino-terminal β domain of mouse MT1, compri...