Search results for "Metallochaperone"

The Arabidopsis heavy metal P-type ATPase HMA5 interacts with metallochaperones and functions in copper detoxification of roots

2005

*† ‡ § Summary Since copper (Cu) is essential in key physiological oxidation reactions, organisms have developed strategies for handling Cu while avoiding its potentially toxic effects. Among the tools that have evolved to cope with Cu is a network of Cu homeostasis factors such as Cu-transporting P-type ATPases that play a key role in transmembrane Cu transport. In this work we present the functional characterization of an Arabidopsis Cutransporting P-type ATPase, denoted heavy metal ATPase 5 (HMA5), and its interaction with Arabidopsis metallochaperones. HMA5 is primarily expressed in roots, and is strongly and specifically induced by Cu in whole plants. We have identified and characteriz…

Metal specificity of the Ni(II) and Zn(II) binding sites of the N-terminal and G-domain of E. coli HypB

2021

HypB is one of the chaperones required for proper nickel insertion into [NiFe]-hydrogenase. Escherichia coli HypB has two potential Ni(II) and Zn(II) binding sites—the N-terminal one and the so-called GTPase one. The metal-loaded HypB–SlyD metallochaperone complex activates nickel release from the N-terminal HypB site. In this work, we focus on the metal selectivity of the two HypB metal binding sites and show that (i) the N-terminal region binds Zn(II) and Ni(II) ions with higher affinity than the G-domain and (ii) the lower affinity G domain binds Zn(II) more effectively than Ni(II). In addition, the high affinity N-terminal domain, both in water and membrane mimicking SDS solution, has a…

Functional and conformational properties of the exclusive C-domain from the Arabidopsis copper chaperone (CCH)

2001

The Arabidopsis thaliana copper chaperone (CCH) is a small copper binding protein involved in copper trafficking. When compared to homologues from other eukaryotes, CCH has two different domains; the conserved N-domain and the plant-exclusive C-domain, a C-terminal extension with an unusual amino-acid composition. In order to characterize this extra C-domain, the CCH protein, the N-domain and the C-domain were all expressed separately in heterologous systems. While the N-domain retained the copper chaperone and antioxidant properties described for the yeast Atx1 and human HAH1 counterparts, the C-domain displayed particular structural properties that would be necessary to optimize copper ho…

2004

Background Arabidopsis thaliana copper metallochaperone CCH is a functional homologue of yeast antioxidant ATX1, involved in cytosolic copper transport. In higher plants, CCH has to be transported to specialised cells through plasmodesmata, being the only metallochaperone reported to date that leaves the cell where it is synthesised. CCH has two different domains, the N-terminal domain conserved among other copper-metallochaperones and a C-terminal domain absent in all the identified non-plant metallochaperones. The aim of the present study was the biochemical and biophysical characterisation of the C-terminal domain of the copper metallochaperone CCH.