Lipid-free apolipoprotein A-I (apoA-I) and A-I(Milano) (A-I(M)) were compared for their denaturation behaviour by running across transverse gradients of a chaotrope, urea, and of a ionic detergent, SDS. For both apo A-I and monomeric apoA-I(M) in the presence of increasing concentrations of urea the transition from high to low mobility had a sigmoidal course, whereas for dimeric A-I(M)/A-I(M) a non-sigmoidal shape was observed. The co-operativity of the unfolding process was lower for dimeric A-I(M)/A-I(M) than for apoA-I or for monomeric apoA-I(M). A slightly higher susceptibility to denaturation was observed for dimeric A-I(M)/A-I(M) than for monomeric apoA-I(M). A similar behaviour of A-I(M)/A-IM versus apoA-I(M) was observed in CD experiments. Large- (12.7/12.5 nm) and small- (7.8 nm) sized reconstituted high-density lipoproteins (rHDL) containing either apoA-I or A-I(M)/A-I(M) were compared with respect to their protein-lipid dissociation behaviour by subjecting them to electrophoresis in the presence of urea, of SDS and of a non-ionic detergent, Nonidet P40. A higher susceptibility to dissociation of small-sized versus large-sized rHDL, regardless of the apolipoprotein component, was observed in all three instances. Our data demonstrate that the differential plasticity of the various classes of rHDL is a function of their size; the higher stability of 12.5/12.7 nm rHDL is likely connected to the higher number of protein-lipid and lipid-lipid interactions in larger as compared with smaller rHDL.
|Titolo:||Size is a major determinant of dissociation and denaturation behaviour of reconstituted high-density lipoproteins|
|Autori interni:||GIANAZZA, ELISABETTA (Primo)|
EBERINI, IVANO (Secondo)
FRANCESCHINI, GUIDO (Penultimo)
CALABRESI, LAURA (Ultimo)
|Parole Chiave:||Apolipoprotein A-I; Non-ionic detergent; Palmitoyloleoyl phosphatidylcholine; Sodium dodecyl sulphate; Urea+ denaturant gradient gel electrophoresis|
|Settore Scientifico Disciplinare:||Settore BIO/10 - Biochimica|
Settore BIO/14 - Farmacologia
|Data di pubblicazione:||2002|
|Digital Object Identifier (DOI):||10.1042/BJ20020058|
|Appare nelle tipologie:||01 - Articolo su periodico|
- PubMed Central loading...