Molecular Basis of Metal-Ion Selectivity and Zeptomolar Sensitivity by CueR

作者：Anita Changela, Kui Chen, Yi Xue, J. Holschen, Caryn E. Outten, Thomas V. O’Halloran, Alfonso Mondragón · 发表于：Science · 年份：2003 · DOI：10.1126/science.1085950 · 被引用次数：673 · 研究领域：Trace Elements in Health、RNA and protein synthesis mechanisms、Bacterial Genetics and Biotechnology

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.