Grasping the nature of the cell interior: from Physiological Chemistry to Chemical Biology.

Current models of the cell interior emphasise its crowded, chemically complex and dynamically organised structure. Although the chemical composition of cells is known, the cooperative intermolecular interactions that govern cell ultrastructure are poorly understood. A major goal of biochemistry is to capture these myriad interactions in vivo. We consider the landmark discoveries that have shaped this objective, starting from the vitalist framework established by early natural philosophers. Through this historical revisionism, we extract important lessons for the bioinspired chemists of today. Scientific specialisation tends to insulate seminal ideas and hamper the unification of paradigms across biology. Therefore, we call for interdisciplinary collaboration in grappling with the complex cell interior. Recent successes in integrative structural biology and chemical biology demonstrate the power of hybrid approaches. The future roles of the (bio)chemist and model systems are also discussed as starting points for in vivo explorations.