A “spindle and thread”-mechanism unblocks translation of N-terminally disordered proteins

Protein disorder is a major hurdle for structural biology. A prominent example is the tumour suppressor p53, whose low expression levels and poor conformational stability due to a high degree of disorder pose major challenges to the development of cancer therapeutics. Here, we address these issues by fusing p53 to an engineered spider silk domain termed NT^*. The chimeric protein displays highly efficient translationin vitroand inE. coliand is fully active in human cancer cells. The transmission electron microscopy structure and native mass spectrometry reveal that the full-length p53 fusion protein adopts a compact conformation. Molecular dynamics simulations show that the disordered transactivation domain of p53 is wound around the NT^*domain via a series of folding events, resulting in a globular structure. We find that expression of B-Raf, another partially disordered cancer target, is similarly enhanced by fusion to NT^*. In summary, we demonstrate how inducing co-translational folding via a molecular “spindle and thread” mechanism can overcome poor translation efficiency of partially disordered proteins.