Reversible Dimerization of Human Serum Albumin
Alexey S. Chubarov, Anna Spitsyna, Olesya A. Krumkacheva, Dmitry Mitin, Daniil Suvorov, Victor M. Tormyshev, Matvey V. Fedin, Michael K. Bowman, Elena G. Bagryanskaya
Abstract
Pulsed Dipolar Spectroscopy (PDS) methods of Electron Paramagnetic Resonance (EPR) were used to detect and characterize reversible non-covalent dimers of Human Serum Albumin (HSA), the most abundant protein in human plasma. The spin labels, MTSL and OX063, were attached to Cys-34 and these chemical modifications of Cys-34 did affect the dimerization of HSA, indicating that other post-translational modifications can modulate dimer formation. At physiologically relevant concentrations, HSA does form weak, non-covalent dimers with a well-defined structure. Dimer formation is readily reversible into monomers. Dimerization is very relevant to the role of HSA in the transport, binding, and other physiological processes.