Since you sent your question to CCP4bb you presumably have crystals! In that case an excellent way to check which metal atoms you have in which sites is to collect datasets at a synchrotron at suitably chosen wavelengths and look at the anomalous maps. For an example see Acta Cryst. D62 (2006) 417-424.
George Prof. George M. Sheldrick FRS Dept. Structural Chemistry, University of Goettingen, Tammannstr. 4, D37077 Goettingen, Germany Tel. +49-551-39-3021 or -3068 Fax. +49-551-39-22582 On Thu, 6 Aug 2009, Xuan Yang wrote: > Dear Sir or Madam, > > The ICP-ES results indicated that 1 molar my protein purified from E.coli > Origami(DE3) contained about a half molar Zinc and nearly a quarter > molar Iron (whether II or III was not available). The protein carried a MBP > tag on the N-terminal and the situation was similar with or without His tag > at the C terminal. I want to determine whether my protein really bind Zinc > or Iron. Does anyone have any experience about such problems? > > Specifically, now I want to compare the binding efficiency on various IMAC, > i.e. 50mM ZnSO4, FeSO4, Fe2(SO4)3, NiSO4(control), or CuSO4(control). > However, considering the instability of Fe(II) in solution, the design > still seemed problematic. > > Sincerely, > > Xuan Yang > > National Laboratory of Biomacromolecules and > Center for Infection and Immunity, > Institute of Biophysics, > Chinese Academy of Sciences, > Room 1617, 15 DaTun Road,Chaoyang District, > Beijing, China, 100101 > Tel: 86-10-64884329 > Academic email: ya...@moon.ibp.ac.cn > We will either find a way or make one. >
