The ferric uptake regulator of Pseudomonas aeruginosa has no essential cysteine residues and does not contain a structural zinc ion

摘要: The ferric uptake regulator (Fur) of Pseudomonas aeruginosa was expressed in Escherichia coli its native form and as a fusion to the maltose-binding protein (MBP). Fur from MBP bound after proteolytic cleavage, two could only be separated by partial unfolding. refolded same conformation (as judged circular dichroism fluorescence spectroscopies) fully active DNA-binding assays. As-prepared contained small amounts Zn2+ that were easily removed treatment with EDTA, apo-protein reconstituted approximately one ion per monomer. Thus, P. can probably accommodate single metal-sensing site. cysteine residue aligns other members family is essential for activity E. protein, believed provide ligands structural ion. This shown dispensable vivo Fur, which consistent suggestion does not contain Members highly conserved His-His-Asp-His motif. Alanine substitutions residues this motif showed His-87 His-89 activity, whilst His-86 Asp-88 are partially dispensable.