Publication Abstract from PubMed
The earliest of a series of copper efflux genes in Escherichia coli are controlled by CueR, a member of the MerR family of transcriptional activators. Thermodynamic calibration of CueR reveals a zeptomolar (10(-21) molar) sensitivity to free Cu+, which is far less than one atom per cell. Atomic details of this extraordinary sensitivity and selectivity for +1transition-metal ions are revealed by comparing the crystal structures of CueR and a Zn2+-sensing homolog, ZntR. An unusual buried metal-receptor site in CueR restricts the metal to a linear, two-coordinate geometry and uses helix-dipole and hydrogen-bonding interactions to enhance metal binding. This binding mode is rare among metalloproteins but well suited for an ultrasensitive genetic switch.
Molecular basis of metal-ion selectivity and zeptomolar sensitivity by CueR.,Changela A, Chen K, Xue Y, Holschen J, Outten CE, O'Halloran TV, Mondragon A Science. 2003 Sep 5;301(5638):1383-7. PMID:12958362[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
