Effects of Macromolecular Crowding in Erythrocyte Cytoplasm

Using Raman spectroscopy, fluorescence spectroscopy, and time-correlated photon counting, it was found that an increase in the temperature of the human erythrocyte incubation medium causes an increase in the homogeneity of hemoglobin distribution in the cytoplasm of erythrocytes and a decrease in the packing density of the globin molecule, which is most likely the result of the effect of “macromolecular crowding” of the cell. The revealed conformational changes are characteristic only of hemoglobin in the cell and do not depend on changes in the surface potential of the plasma membrane. It is assumed that there are several pools of hemoglobin molecules that differ in the structure and dynamics of the protein globule, forming a heterogeneous distribution of hemoglobin inside the erythrocyte due to the combining of hemoglobin molecules into clusters. The possibility of the involvement of these effects in the signaling and regulatory function of oxygen transport and transport is discussed.