Density Functional Calculations on the Interaction Between Catabolite Activator Protein and Cyclic Amp Using the Fragment Molecular Orbital Method

The specific interaction between catabolite activator protein (CAP) and cyclic adenosine monophosphate (cAMP) was investigated using the fragment molecular orbital method based on density functional theory (FMO-DFT). One of the efficient tools of FMO-DFT is the analysis of effective pair interactions, which are the pairwise fragment interactions under the influence of electrostatic potentials from surrounding fragments. We investigated the specific interaction between CAP/mutated-CAP and cAMP/cGMP to elucidate the effect of amino-acid mutations in CAP on the CAP-cAMP as well as CAP-cGMP interactions.