The systems perspective at the crossroads between chemistry and biology.

During the last century a number of authors pointed to the inherently systemic and dynamic nature of the living, yet their message was largely ignored by the mainstream of the scientific community. Tibor Ganti was one of those early pioneers, proposing a theoretical framework to understand the living principles in terms of chemical transformation cycles and their coupling. The turn of the century then brought with it a novel 'systems' paradigm, which shined light on all that previous work and carried many implications for the way we conceive of chemical and biological complexity today. In this article tribute is paid to some of those seminal contributions, highlighting the importance of adopting a systems view in present chemistry, particularly if plausible mechanisms of chemical evolution toward the first living entities want to be unraveled. We examine and put in perspective recent discoveries in the emerging subfield of 'prebiotic systems chemistry', reaching the conclusion that the functional coupling of protocellular subsystems (i.e., protometabolism, protogenome and membrane compartment) is the most challenging target to make qualitative advances in the problem of the origins of life. For the long-awaited goal of assembling an autonomous protocell from its most basic molecular building blocks, we further suggest that a systems integrative strategy should be considered from the earliest synthetic steps, already at the level of monomer precursors, opening the way to biogenesis.