Final answer:
The N-end rule refers to the recognition of specific N-terminal amino acids by E3 ubiquitin ligases, which influences the stability and half-life of the protein. Strong stabilizers include amino acids like GPMV and SAT, while strong destabilizers include RK, LFWY.
Step-by-step explanation:
When referring to the N-end rule in protein degradation, it relates to the recognition of N-terminal amino acids of a protein, which can determine the protein's stability and half-life. The rule classifies amino acids based on their effect on the protein's stability. According to the N-end rule, strong stabilizing amino acids (grades 1 and 2; GPMV, SAT) lead to a long half-life of proteins bearing these at the N-terminus, while strong destabilizers (grades 8 and 9; RK, LFWY) result in a drastically shortened protein half-life. The E3 ubiquitin ligases recognize these N-terminal amino acids as a signal for protein degradation.