Thermodynamic analysis of the conformational stability of a single-domain therapeutic antibody

The stability of a new single-domain therapeutic antibody to the ErbB3 receptor was studied by fluorescence spectroscopy at different concentrations of a denaturing agent and temperatures. The analysis of experimental denaturation curves allowed us to build a complete thermodynamic model of unfolding and to determine all parameters of the transition: $\Delta G$ = 8.5 kcal $\cdot$ mol$^{-1}$, $T_{m}$ = 76$^\circ$C, $\Delta H_{m}$ = 107 kcal $\cdot$ mol$^{-1}$, $\Delta C_{p}$ = 1.8 kcal $\cdot$ K$^{-1}$ $\cdot$ mol$^{-1}$. The obtained data evidence the high stability of the antibody in a broad range of conditions, which is essential for further structural and functional studies and possible therapeutic application.