Before revision:  Here  we predict that for a large class of biomolecular interactions  it is possible to accurately estimate the relative free energy of binding based on the fluctuation properties of their energy spectra, even if a finite number of the energy levels is known.
After revision:  Here , using a variant of the Derrida model, we predict that for a large class of biomolecular interactions it is possible to accurately estimate the relative free energy of binding based on the fluctuation properties of their energy spectra, even if a finite number of the energy levels is known.