The article examines the structural ontogeny of protein-protein interactions, i.e. the development of protein binding sites during evolution[3][4]. By Yang A., Jiang H., Jude K.M. and others published the study in the journal Science (Volume 391, Number 6786, February 2026)[3]. An example is the co-evolved affibody pair A5B5 with PDB code 9NKP[3]. Natural protein binding sites are often the most suitable for drug targeting ('druggable'), while alternative protein surfaces present challenging targets[4][6]. Understanding the evolution of these binding sites may aid in targeting "non-druggable" surfaces[4]. The study highlights the importance of protein surfaces in regulating physical contact and recognition between proteins[1]. The data is available on the Dryad platform[6].