2l55

Publication Abstract from PubMed

Detoxification of heavy metal ions in Proteobacteria is tightly controlled by various systems regulating their sequestration and transport. In Cupriavidus metallidurans CH34, a model organism for heavy metal resistance studies, the sil determinant is potentially involved in silver and copper ions efflux. Proteins SilA, SilB, and SilC form a Resistance Nodulation cell Division (RND)-based transport system where SilB is the periplasmic adaptor protein belonging to the Membrane Fusion Protein (MFP) family. In addition to the four domains typical of known MFPs, SilB has a fifth additional C-terminal domain, called SilB440-521, which is characterized here. Structure and backbone dynamics of SilB440-521 have been investigated using NMR and the residues of the metal site were identified from 15N and 13C-edited HSQC spectra. The solution structure and additional metal binding experiments demonstrated that this C-terminal domain folds independently of the rest of the protein and has a conformation and a Ag+ and Cu+ binding specificity similar to those determined for CusF from Escherichia coli. The small protein CusF plays a role in metal-trafficking in the periplasm. The similarity with CusF suggests a potential metallochaperone role for SilB440-521 that is discussed in the context of simultaneous expression of different determinants involved in copper resistance in C. metallidurans CH34.

Structural and metal-binding characterization of the C-terminal metallochaperone domain of the membrane fusion protein SilB from Cupriavidus metallidurans CH34.,Bersch B, Derfoufi KM, De Angelis F, Auquier V, Ngolong Ekende E, Mergeay M, Ruysschaert JM, Vandenbussche G Biochemistry. 2011 Feb 7. PMID:21299248^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.