Crystal structures of the copper and nickel complexes of RNase A: Metal-induced interprotein interactions and identification of a novel copper binding motif
AUTOR(ES)
Balakrishnan, R.
FONTE
The National Academy of Sciences of the USA
RESUMO
We report the crystal structures of the copper and nickel complexes of RNase A. The overall topology of these two complexes is similar to that of other RNase A structures. However, there are significant differences in the mode of binding of copper and nickel. There are two copper ions per molecule of the protein, but there is only one nickel ion per molecule of the protein. Significant changes occur in the interprotein interactions as a result of differences in the coordinating groups at the common binding site around His-105. Consequently, the copper- and nickel-ion-bound dimers of RNase A act as nucleation sites for generating different crystal lattices for the two complexes. A second copper ion is present at an active site residue His-119 for which all the ligands are from one molecule of the protein. At this second site, His-119 adopts an inactive conformation (B) induced by the copper. We have identified a novel copper binding motif involving the α-amino group and the N-terminal residues.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=23236Documentos Relacionados
- Metal-induced infidelity during DNA synthesis.
- Hydroxymethyl-phytochelatins [(gamma-glutamylcysteine)n-serine] are metal-induced peptides of the Poaceae.
- The transcription factor MTF-1 is essential for basal and heavy metal-induced metallothionein gene expression.
- Zn2+-sensing by the cyanobacterial metallothionein repressor SmtB: different motifs mediate metal-induced protein-DNA dissociation.
- Rack-induced metal binding vs. flexibility: Met121His azurin crystal structures at different pH