A recent study, led by Centro de Astrobiologia (CAB), INTA-CSIC, and the Centro Nacional de Biotecnologia  (CNB-CSIC), shows the experimental structural reconstruction of the most primitive multimeric proteins to date, that is, those early machines built from protein units that assemble to generate a new biological function.  The work contributes to deciphering the evolutionary path of chaperonins, one of the most universal molecular machines in life, essential for the correct folding of proteins in both the simplest and most primitive bacteria and in humans.