Wang, K. H., Oakes, E. S. C., Sauer, R. T. & Baker, T. A. Tuning the strength of a bacterial N-end rule degradation signal. J. Biol. Chem. 283, 24600–24607 (2008).

In this publication, Wang and colleagues elucidate rules governing degradation of N-end rule signals. This rule determines that there will be a higher instability (and degradation rate) of proteins with certain N' terminal amino acids. Which amino acid is present is the most influential factor, but distance from the structurally sable region and presence of acidic amino acids near the N-end also modulate this dynamic. No exact quantitative values are explicited, so here we just display general strength values.