title: Evidence for the molten globule state of human apo-ceruloplasmin.
abstract: The conformational features of copper-free ceruloplasmin (CP), as compared to the holo-protein, were evaluated utilizing far- and near-UV circular dichroism and fluorescence spectroscopy. The results obtained indicate that apo-CP maintains the secondary structure of the holo-protein, while the tertiary interactions are much weaker. In addition, the removal of copper from the holo-protein leads to the exposure of hydrophobic patches to solvent, as shown by the fact that apo-CP, at variance from the holo-protein, binds the hydrophobic probe ANS. It is proposed that the CP molecule, upon copper removal, acquires the conformational features typical of a molten globule, which might be the conformational state of CP during its biosynthesis before metal incorporation.
authors.affiliation: CRIBI Biotechnology Centre, University of Padua, Italy.
authors.forename: V
authors.initials: V
authors.lastname: De Filippis
authors.forename: V B
authors.initials: VB
authors.lastname: Vassiliev
authors.forename: M
authors.initials: M
authors.lastname: Beltramini
authors.forename: A
authors.initials: A
authors.lastname: Fontana
authors.forename: B
authors.initials: B
authors.lastname: Salvato
authors.forename: V S
authors.initials: VS
authors.lastname: Gaitskhoki
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000378:metabolism; D001059:Apoproteins / Q000737:chemistry*; D002570:Ceruloplasmin / Q000737:chemistry*; D002942:Circular Dichroism; D003300:Copper / Q000378:metabolism / Q000494:pharmacology*; D006527:Hepatolenticular Degeneration / Q000503:physiopathology; D006801:Humans; D008667:Metalloproteins / Q000737:chemistry; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013050:Spectrometry, Fluorescence
chemical_list: D000817:Anilino Naphthalenesulfonates; D001059:Apoproteins; D008667:Metalloproteins; C006612:apoceruloplasmin; C027132:1-anilino-8-naphthalenesulfonate; D003300:Copper; D002570:Ceruloplasmin