title: Mechanism of Lysine 48 Selectivity during Polyubiquitin Chain Formation by the Ube2R1/2 Ubiquitin-Conjugating Enzyme.
abstract: Lysine selectivity is of critical importance during polyubiquitin chain formation because the identity of the lysine controls the biological outcome. Ubiquitins are covalently linked in polyubiquitin chains through one of seven lysine residues on its surface and the C terminus of adjacent protomers. Lys 48-linked polyubiquitin chains signal for protein degradation; however, the structural basis for Lys 48 selectivity remains largely unknown. The ubiquitin-conjugating enzyme Ube2R1/2 has exquisite specificity for Lys 48, and computational docking of Ube2R1/2 and ubiquitin predicts that Lys 48 is guided to the active site through a key electrostatic interaction between Arg 54 on ubiquitin and Asp 143 on Ube2R1/2. The validity of this interaction was confirmed through biochemical experiments. Since structural examples involving Arg 54 in protein-ubiquitin complexes are exceedingly rare, these results provide additional insight into how ubiquitin-protein complexes can be stabilized. We discuss how these findings relate to how other ubiquitin-conjugating enzymes direct the lysine specificity of polyubiquitin chains.
authors.affiliation: Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada, USA.
authors.forename: Spencer
authors.initials: S
authors.lastname: Hill
authors.affiliation: Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Harrison
authors.affiliation: Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Lewis
authors.affiliation: Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Kuhlman
authors.affiliation: Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada, USA gary.kleiger@unlv.edu.
authors.forename: Gary
authors.initials: G
authors.lastname: Kleiger
mesh_terms: D001120:Arginine / Q000378:metabolism; D001224:Aspartic Acid / Q000378:metabolism; D020134:Catalytic Domain; D006801:Humans; D008239:Lysine / Q000378:metabolism*; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D025821:Polyubiquitin / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D044763:Ubiquitin-Conjugating Enzymes / Q000737:chemistry* / Q000378:metabolism
chemical_list: D025821:Polyubiquitin; D001224:Aspartic Acid; D001120:Arginine; C577447:CDC34 protein, human; C000619241:Ube2R2 protein, human; D044763:Ubiquitin-Conjugating Enzymes; D008239:Lysine