Binding energy and the information content of some elementary biological processes

Abstract

Protein interactions within a multimolecular complex can result in information and energy transfer between proteins. This can lead in turn to the emergence of novel functions of some proteins of the complex. Various examples of this situation can be found in the scientific literature. This is probably the case for prion protein, chloroplast phosphoribulokinase bound to glyceraldehyde phosphate dehydrogenase, Ras system, and pancreatic lipase bound to biomembranes, to cite but a few. Any enzyme reaction, or enzyme reaction network, carries Shannon entropy and information. On contrary to genome entropy, the entropy of enzyme reactions and metabolic sequences is sensitive to ‘external’ signals, such as substrate, effector and proton concentrations. Complex structural organization of the cell is associated with a higher entropy content, and one can calculate the gain of entropy and information due to integration and complexity. One may conclude from this brief analysis that the informational content of a living cell is much larger than that of its genome.