The configuration of the Cu(2+) binding region in full-length human prion protein compared with the isolated octapeptide.

The cellular prion protein (PrP(C)) is a copper binding protein. The molecular features of the Cu(2+) binding sites have been investigated and characterized by spectroscopic experiments on PrP(C)-derived peptides and the correctly folded human full-length PrP(C) (hPrP-[23-231]). These experiments allowed us to distinguish two different configurations of copper binding.

The configuration of the Cu2+ binding region in full-length human prion protein.

The cellular prion protein (PrP(C)) is a Cu(2+) binding protein connected to the outer cell membrane. The molecular features of the Cu(2+) binding sites have been investigated and characterized by spectroscopic experiments on PrP(C)-derived peptides and the recombinant human full-length PrP(C )(hPrP-[23-231]). The hPrP-[23-231] was loaded with (63)Cu under slightly acidic (pH 6.

A new method to determine the structure of the metal environment in metalloproteins: investigation of the prion protein octapeptide repeat Cu(2+) complex.

Since high-intensity synchrotron radiation is available, "extended X-ray absorption fine structure" spectroscopy (EXAFS) is used for detailed structural analysis of metal ion environments in proteins. However, the information acquired is often insufficient to obtain an unambiguous picture. ENDOR spectroscopy allows the determination of hydrogen positions around a metal ion.

Micellar environments induce structuring of the N-terminal tail of the prion protein.

In the physiological form, the prion protein is a glycoprotein tethered to the cell surface via a C-terminal glycosylphosphatidylinositol anchor, consisting of a largely alpha-helical globular C-terminal domain and an unstructured N-terminal portion. This unstructured part of the protein contains four successive octapeptide repeats, which were shown to bind up to four Cu(2+) ions in a cooperative manner. To mimic the location of the protein on the cell membrane and to analyze possible structuring effects of the lipid/water interface, the conformational preferences of a single octapeptide repeat and its tetrameric form, as well of the fragment 92-113, proposed as an additional copper binding site, were comparatively analyzed in aqueous and dodecylphosphocholine micellar solution as a membrane mimetic.

Binding of vanadate to human albumin in infusion solutions, to proteins in human fresh frozen plasma, and to transferrin.

The binding of vanadate (V) to human serum albumin (HSA) in infusion solutions, to human fresh frozen plasma (FFP), and to human transferrin (TF) was investigated over a wide concentration range. Free V concentrations were obtained by ultrafiltration. Total and free V concentrations were determined using electrothermal atomic absorption spectrometry (ETAAS).