title: The molecular basis for the post-translational addition of amino acids by L/F transferase in the N-end rule pathway.
abstract: The N-end rule pathway is a conserved targeted proteolytic process observed in organisms ranging from eubacteria to mammals. The N-end rule relates the metabolic stability of a protein to its N-terminal amino acid residue. The identity of the N-terminal amino acid residue is a primary degradation signal, often referred to as an N-degron, which is recognized by the components of the N-end rule when it is a destabilizing N-terminus. N-degrons may be exposed by non-processive proteolytic cleavages or by post-translational modifications. One modification is the post-translational addition of amino acids to the N-termini of proteins, a reaction catalyzed by aminoacyl-tRNA protein transferases. The aminoacyl-tRNA protein transferase in eubacteria like Escherichia coli is L/F transferase. Recent investigations have reported unexpected observations regarding the L/F transferase catalytic mechanism and its mechanisms of substrate recognition. Additionally, recent proteome-wide identification of putative in vivo substrates facilitates hypothesis into the yet elusive biological functions of the prokaryotic N-end rule pathway. Here we summarize the recent findings on the molecular mechanisms of catalysis and substrate recognition by the E. coli L/F transferase in the prokaryotic N-end rule pathway.
authors.forename: Angela Wai S
authors.initials: AW
authors.lastname: Fung
authors.affiliation: 474 Medical Sciences Building, Department of Biochemistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada. rfahlman@ualberta.ca.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Fahlman
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism*; D019881:Aminoacyltransferases / Q000737:chemistry / Q000378:metabolism*; D002384:Catalysis; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D011499:Protein Processing, Post-Translational; D059748:Proteolysis; D012343:RNA, Transfer / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D000596:Amino Acids; D012343:RNA, Transfer; D019881:Aminoacyltransferases; C019675:tRNA-protein transferase, amino acyl