title: Zinc to cadmium replacement in the A. thaliana SUPERMAN Cys₂ His₂ zinc finger induces structural rearrangements of typical DNA base determinant positions.
abstract: Among heavy metals, whose toxicity cause a steadily increasing of environmental pollution, cadmium is of special concern due to its relatively high mobility in soils and potential toxicity at low concentrations. Given their ubiquitous role, zinc fingers domains have been proposed as mediators for the toxic and carcinogenic effects exerted by xenobiotic metals. To verify the structural effects of zinc replacement by cadmium in zinc fingers, we have determined the high resolution structure of the single Cys₂ His₂ zinc finger of the Arabidopsis thaliana SUPERMAN protein (SUP37) complexed to the cadmium ion by means of UV-vis and NMR techniques. SUP37 is able to bind Cd(II), though with a dissociation constant higher than that measured for Zn(II). Cd-SUP37 retains the ββα fold but experiences a global structural rearrangement affecting both the relative orientation of the secondary structure elements and the position of side chains involved in DNA recognition: among them Ser17 side chain, which we show to be essential for DNA binding, experiences the largest displacement.
authors: Dipartimento di Scienze Ambientali, II University of Naples, via Vivaldi 43, 81100 Caserta, Italy.
authors: Gaetano
authors: G
authors: Malgieri
authors: Laura
authors: L
authors: Zaccaro
authors: Marilisa
authors: M
authors: Leone
authors: Enrico
authors: E
authors: Bucci
authors: Sabrina
authors: S
authors: Esposito
authors: Ilaria
authors: I
authors: Baglivo
authors: Annarita
authors: A
authors: Del Gatto
authors: Luigi
authors: L
authors: Russo
authors: Roberto
authors: R
authors: Scandurra
authors: Paolo V
authors: PV
authors: Pedone
authors: Roberto
authors: R
authors: Fattorusso
authors: Carla
authors: C
authors: Isernia