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Zinc to cadmium replacement in the A. thaliana SUPERMAN Cys2His2 zinc finger induces structural rearrangements of typical DNA base determinant positionsZinc to cadmium replacement in the A. thaliana SUPERMAN Cys2His2 zinc finger induces structural rearrangements of typical DNA base determinant positions
Structural highlights
FunctionSUP_ARATH Probable transcriptional regulator considered as cadastral protein that acts indirectly to prevent the B class homeotic proteins APETALA3 and perhaps PISTILLATA from acting in the gynoecial whorl. Principal function is to balance cell proliferation in the third and fourth whorls of developing flowers thereby maintaining the boundary between stamens and carpels. May fulfill this role by repressing genes implicated in cell division. Plays equally a role in the determinacy of the floral meristem. Is also required for normal ovule development.[1] [2] [3] [4] [5] Publication Abstract from PubMedAmong 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 Cys(2) His(2) zinc finger of the A. 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 betabetaalpha 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. (c) 2011 Wiley Periodicals, Inc. Biopolymers, 2011. Zinc to cadmium replacement in the A. thaliana SUPERMAN Cys(2) His(2) zinc finger induces structural rearrangements of typical DNA base determinant positions.,Malgieri G, Zaccaro L, Leone M, Bucci E, Esposito S, Baglivo I, Del Gatto A, Russo L, Scandurra R, Pedone PV, Fattorusso R, Isernia C Biopolymers. 2011 May 25. doi: 10.1002/bip.21680. PMID:21618209[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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