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Title of article :
An X-ray diffraction and X-ray absorption spectroscopy joint study of neuroglobin
Author/Authors :
Arcovito، نويسنده , , Alessandro and Moschetti، نويسنده , , Tommaso and D’Angelo، نويسنده , , Paola and Mancini، نويسنده , , Giordano and Vallone، نويسنده , , Beatrice and Brunori، نويسنده , , Maurizio and Della Longa، نويسنده , , Stefano، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2008
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Abstract :
Neuroglobin (Ngb) is a member of the globin family expressed in the vertebrate brain, involved in neuroprotection. A combined approach of X-ray diffraction (XRD) on single crystal and X-ray absorption spectroscopy (XAS) in solution, allows to determine the oxidation state and the structure of the Fe–heme both in the bis-histidine and the CO-bound (NgbCO) states. The overall data demonstrate that under X-ray the iron is photoreduced fairly rapidly, and that the previously reported X-ray structure of ferric Ngb [B. Vallone, K. Nienhaus, M. Brunori, G.U. Nienhaus, Proteins 56 (2004) 85–92] very likely refers to a photoreduced species indistinguishable from the dithionite reduced protein. Results from the XAS analysis of NgbCO in solution are in good agreement with XRD data on the crystal. However prolonged X-ray exposure at 15 K determines CO release. This preliminary result paves the way to experiments aimed at the characterization of pentacoordinate ferrous Ngb, the only species competent in binding external ligands such as O2, CO or NO.
Keywords :
EXAFS , hemeproteins , XANES , neuroprotection , Synchrotron radiation
Journal title :
Archives of Biochemistry and Biophysics
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