@article{open3289,
          volume = {64},
          number = {13},
           month = {July},
          author = {Manisha Yadav and Sureshan Muthusamy and Saraboji Kadhirvel and Deepak Sharma and Rajesh Kumar},
           title = {Determining factors for spermidine-induced modulation of conformational stability and dynamics of horse myoglobin},
       publisher = {American Chemical Society (ACS)},
            year = {2025},
         journal = {Biochemistry},
           pages = {2899--2915},
             url = {http://crdd.osdd.net/open/3289/},
        abstract = {The present work describes how water-miscible natural polyamine (NPA) spermidine (SPD) alters the conformational stability and dynamics of horse myoglobin (h-Mb) at pH 7.4. Analysis of thermal- and chemical-induced unfolding profiles of h-Mb at different concentrations of SPD at pH 7.4 revealed that SPD ({$\backslash$}geq5 mM) reduces the conformational stability of h-Mb. The effect of SPD was further corroborated using MD simulations, which showed that SPD ({$\backslash$}geq5 mM) enhanced the conformational fluctuations and reduced the structural stability of h-Mb. The SPD concentration effect on the thermodynamic equilibria (KU) of h-Mb was translated to the changes in preferential interaction coefficient ({\ensuremath{\Delta}}{\ensuremath{\Gamma}}23) and hydration number ({\ensuremath{\Delta}}{\ensuremath{\Gamma}}w). The finding of the positive value of {\ensuremath{\Delta}}{\ensuremath{\Gamma}}23 and the negative value of {\ensuremath{\Delta}}{\ensuremath{\Gamma}}w suggests that the interaction of SPD with h-Mb and the exclusion of water from the protein reduce the conformational stability of h-Mb. Analysis of SPD effects on enthalpy-entropy plots and temperature dependence of unfolding free energy of h-Mb suggests that the SPD forms soft, attractive enthalpic interactions with h-Mb. Analysis of SPD impact on the urea-concentration-dependent thermal unfolding midpoint temperature showed that SPD exhibits an additive effect to the urea-mediated decrease in the thermal stability of h-Mb.}
}