title: Destabilization of CH2 domains in intact IgG2 is accompanied by reduced ability to inhibit complement system factor C1.
abstract: Fc fragments (hFc) of human myeloma IgG2 proteins LOM and SIN having core hinge (Cys-Cys-Val-Glu-Cys-Pro-Pro-Cys) were first obtained by a modified proteolytic procedure. The thermostability of CH2 domains inside of standard Fc, hFc fragments, and intact IgG2 LOM and SIN was studied by fluorescence spectroscopy. It was found that CH2 domains of intact IgG2 are destabilized. The destabilization is accompanied by reduced ability of IgG2 to inhibit the activation of complement system by classical pathway. This could be due to the decrease in the affinity of CH2 domains to factor C1q.
authors: Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 143390 Pushchino, Moscow Region, Russia.
authors: M A
authors: MA
authors: Timchenko
authors: V M
authors: VM
authors: Tischenko
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003172:Complement C1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007127:Immunoglobulin Constant Regions / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D007141:Immunoglobulin Fc Fragments / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D007074:Immunoglobulin G / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding; D055550:Protein Stability; D011817:Rabbits; D013050:Spectrometry, Fluorescence; D013696:Temperature; D013816:Thermodynamics
chemical_list: D003172:Complement C1; D007127:Immunoglobulin Constant Regions; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G