[Aggregation of C-reactive protein in solutions at acid pH].
The hydrodynamic properties of the C-reactive protein (CRP) at different pH were studied using quasi-elastic light scattering, size-exclusion liquid chromatography, and nonreducing gel electrophoresis. It was shown that a CRP solution at pH 5.0-7.2 presents a polydisperse system the major component of which is the native pentameric CRP. At pH 4.0-4.5, CRP exists in two states having different hydrodynamic properties: the native pentameric form with a molecular mass of 120 kDa and with the hydrodynamic radius of 4.03 nm and high-molecular-weight aggregates with a wide range of their molecular weight distribution. The interaction of the C-reactive protein with monoclonal antibodies to it indicates that conformation-dependent surface epitopes of the protein lose the native structure at pH 5.0-5.5. The aggregation of CRP is an irreversible process, which begins in a narrow pH range of pH 5.0-4.5 and is not accompanied by the dissociation into subunits but is determined by intermolecular interactions of its quasi-native pentamers.
Blizniukov
O P
OP
Institute of Immunology, Ministry of Health of Russian Federation, Kashirskoe shosse 24/2, Moscow, 115478 Russia. blisnukov@mail.ru
Kozmin
L D
LD
Falikova
V V
VV
Martynov
A I
AI
Tishchenko
V M
VM
D000143:Acids / Q000737:chemistry*; D002097:C-Reactive Protein / Q000737:chemistry*; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008027:Light; D012542:Scattering, Radiation; D012996:Solutions
D000143:Acids; D012996:Solutions; D002097:C-Reactive Protein