The cellular prion protein, the precursor of the major protein component of prions, is a Cu(II) binding protein. Cooperative cation binding occurs in the flexible N-terminal protein domain that is characterized by a highly conserved octarepeat segment. The Cu(II) site geometry in synthetic peptides containing multiple copies of the octarepeat and in the a-like form of BoPrP (24-242) in complexes with Cu(II) ions at various equivalences has been studied using X-ray absorption spectroscopy (XAS). Inspection of the near edge region of the spectra confirms that upon binding Cu(II) preserves its oxidation state. Accurate analysis of the extended region of the XAS spectra in terms of a multiple-scattering approach shows the occurrence of two types of coordination geometries. The modeled geometries for the alternative Cu(II) bindings provide a structural ground for a positive cooperativity mechanism underlying the cation binding process.
Morante, S., Potrich, C., GONZALES IGLESIAS, R., Meneghini, C., MEYER KLAUCKE, W., Menestrina, G., et al. (2004). XAS-analysis reveals two Cu(II) site geometries in prion protein complexes.
XAS-analysis reveals two Cu(II) site geometries in prion protein complexes
MENEGHINI, CARLO;
2004-01-01
Abstract
The cellular prion protein, the precursor of the major protein component of prions, is a Cu(II) binding protein. Cooperative cation binding occurs in the flexible N-terminal protein domain that is characterized by a highly conserved octarepeat segment. The Cu(II) site geometry in synthetic peptides containing multiple copies of the octarepeat and in the a-like form of BoPrP (24-242) in complexes with Cu(II) ions at various equivalences has been studied using X-ray absorption spectroscopy (XAS). Inspection of the near edge region of the spectra confirms that upon binding Cu(II) preserves its oxidation state. Accurate analysis of the extended region of the XAS spectra in terms of a multiple-scattering approach shows the occurrence of two types of coordination geometries. The modeled geometries for the alternative Cu(II) bindings provide a structural ground for a positive cooperativity mechanism underlying the cation binding process.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
