Binding of recombinant PrPc to human plasminogen: kinetic and thermodynamic study using a resonant mirror biosensor.
Transmissible spongiform encephalopathies are a class of sporadic, genetic and transmissible neurodegenerative diseases that affect both humans and animals. Propagation of these diseases is thought to be due to the misfolding of a neuronal glyco-protein, PrP(c), into a pathological insoluble conformer, PrP(Sc). In earlier works, some serum components were identified as exclusive PrP(Sc)-interacting proteins (Fisher et al., Nature 2000;408:479), and thus those macromolecules were thought to represent a potential diagnostic endogenous factor discriminating between normal and pathological prion proteins. In contrast, in agreement with a recent work (Kornblatt et al., Biochem Biophys Res Commun 2003;305:518), in this paper we present a detailed thermodynamic and kinetic characterization of the interaction between recombinant bovine PrP(c 25-242) and the human serum component plasminogen, measured using a resonant mirror technique: our results reveal a high-affinity interaction between the two binding partners. For comparison, the complex obtained from the purified full-length PrP(c) and human plasminogen was also studied: both prion proteins (the recombinant bovine PrP(c 25-242) and the purified full-length PrP(c)) are able to bind human plasminogen. Both kinetic and thermodynamic parameters are affected by the modulation exerted by the H(+) ions in solution. Moreover, the analysis of binding, according to canonical linkage relationships, suggests the involvement of a His residue, consistent with the interaction between other serine (pro)enzymes and their ligands.
Cuccioloni
Massimiliano
M
MCAB Department, University of Camerino, Italy. massimiliano.cuccioloni@unicam.it <massimiliano.cuccioloni@unicam.it>
Amici
Manila
M
Eleuteri
Anna Maria
AM
Biagetti
Massimo
M
Barocci
Simone
S
Angeletti
Mauro
M
D000818:Animals; D015374:Biosensing Techniques; D002417:Cattle; D002845:Chromatography; D006031:Glycosylation; D006639:Histidine / Q000737:chemistry; D006801:Humans; D006859:Hydrogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007700:Kinetics; D008024:Ligands; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase / Q000737:chemistry; D010958:Plasminogen / Q000737:chemistry*; D018621:PrPC Proteins / Q000737:chemistry*; D018620:PrPSc Proteins / Q000737:chemistry*; D011328:Prions / Q000737:chemistry; D011485:Protein Binding; D020033:Protein Isoforms; D011506:Proteins / Q000737:chemistry; D040901:Proteomics / Q000379:methods*; D011522:Protons; D011994:Recombinant Proteins / Q000737:chemistry*; D013329:Structure-Activity Relationship; D013816:Thermodynamics
D007477:Ions; D008024:Ligands; D018621:PrPC Proteins; D018620:PrPSc Proteins; D011328:Prions; D020033:Protein Isoforms; D011506:Proteins; D011522:Protons; D011994:Recombinant Proteins; D006639:Histidine; D006859:Hydrogen; D010958:Plasminogen; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase