title: Structures of the SUMO E1 provide mechanistic insights into SUMO activation and E2 recruitment to E1.
abstract: E1 enzymes facilitate conjugation of ubiquitin and ubiquitin-like proteins through adenylation, thioester transfer within E1, and thioester transfer from E1 to E2 conjugating proteins. Structures of human heterodimeric Sae1/Sae2-Mg.ATP and Sae1/Sae2-SUMO-1-Mg.ATP complexes were determined at 2.2 and 2.75 A resolution, respectively. Despite the presence of Mg.ATP, the Sae1/Sae2-SUMO-1-Mg.ATP structure reveals a substrate complex insomuch as the SUMO C-terminus remains unmodified within the adenylation site and 35 A from the catalytic cysteine, suggesting that additional changes within the adenylation site may be required to facilitate chemistry prior to adenylation and thioester transfer. A mechanism for E2 recruitment to E1 is suggested by biochemical and genetic data, each of which supports a direct role for the E1 C-terminal ubiquitin-like domain for E2 recruitment during conjugation.
authors.affiliation: Structural Biology Program, Sloan-Kettering Institute, New York, NY 10021, USA.
authors.forename: Luisa Maria
authors.initials: LM
authors.lastname: Lois
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Lima
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D019281:Dimerization; D004789:Enzyme Activation; D006801:Humans; D066298:In Vitro Techniques; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D000075687:NEDD8 Protein; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D025842:SUMO-1 Protein / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D044764:Ubiquitin-Activating Enzymes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014452:Ubiquitins / Q000378:metabolism
chemical_list: D046912:Multiprotein Complexes; D000075687:NEDD8 Protein; C082860:NEDD8 protein, human; D011994:Recombinant Proteins; D025842:SUMO-1 Protein; C470301:UBA2 protein, human; D014452:Ubiquitins; D000255:Adenosine Triphosphate; C470299:SAE1 protein, human; D044764:Ubiquitin-Activating Enzymes