In vivo half-life of a protein is a function of its amino-terminal residue

摘要: When a chimeric gene encoding ubiquitin-beta-galactosidase fusion protein is expressed in the yeast Saccharomyces cerevisiae, ubiquitin cleaved off nascent protein, yielding deubiquitinated beta-galactosidase (beta gal). With one exception, this cleavage takes place regardless of nature amino acid residue beta gal at ubiquitin-beta junction, thereby making it possible to expose different residues amino-termini otherwise identical proteins. The proteins thus designed have strikingly half-lives vivo, from more than 20 hours less 3 minutes, depending on amino-terminus gal. set individual acids can be ordered with respect that they confer when present its (the "N-end rule"). currently known amino-terminal long-lived, noncompartmentalized intracellular both prokaryotes and eukaryotes belong exclusively stabilizing class as predicted by N-end rule. function previously described posttranslational addition single may also accounted for Thus recognition an mediate metabolic stability potential regulation stability.