PECULIARITY OF BIS-(3′, 5′)-CYCLIC DIMERIC GUANOSINE MONOPHOSPHATE BINDING TO HUMAN HEMOGLOBIN TETRAMERS

Abstract

Molecular modeling complexes of bis-(3′, 5′)-cyclic dimeric guanosine monophosphate (c-di-GMP) with human oxyhemoglobin HbA1 and the analysis of the cyclic diguanylic acid inhibitory effect on the binding of 1,8-ANS to HbA1 carried out by the steady-state fluorescence spectroscopy showed that the most specific binding site of c-di-GMP in hemoglobin oligomers is the central regulatory region of this protein (competitive inhibition constant is 2.91 ± 0.54·10⁻⁵ М). At high concentrations of 1,8-ANS c-di-GMP inhibitory effect on the probe binding is non-competitive (non-competitive inhibition constant is 0.79 ± 0.11·10⁻⁴ М), indicating the ability of c-di-GMP interact with less specific surface areas of human oxyhemoglobin.