title: Analysis of electrostatic contributions to the selectivity of interactions between RING-finger domains and ubiquitin-conjugating enzymes.
abstract: The zinc-coordinated protein motifs known as RING-finger domains, present on a class of ubiquitin ligases (E3's), recruit ubiquitin-conjugating enzymes (E2s), tethering them to substrate proteins for covalent modification with ubiquitin. Each RING-finger domain can recruit different E2s, and these interactions are frequently selective, in that certain RING-finger domains associate preferentially with certain E2s. This selectivity acquires particular biological relevance when the recruited E2s exert specialized functions. We have explored the determinants that specify the presence or absence of experimentally detectable interaction between two RING-finger domains, those on RNF11 and RNF103, and two E2s, UBC13, a specialized E2 that catalyzes ubiquitin chain elongation through Lys63 of ubiquitin, and UbcH7, which mediates polyubiquitylation through Lys48. Through the iterative use of computational predictive tools and experimental validations, we have found that these interactions and their selectivity are partly governed by the combinations of electrostatic interactions linking specific residues of the contact interfaces. Our analysis also predicts that the main determinants of selectivity of these interactions reside on the RING-finger domains, rather than on the E2s. The application of some of these rules of interaction selectivity has permitted us to experimentally manipulate the selectivity of interaction of the RING-finger domain-E2 pairs under study.
authors.affiliation: Department of Molecular and Cell Biology, Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Barcelona, Spain.
authors.forename: Johanna
authors.initials: J
authors.lastname: Scheper
authors.forename: Baldo
authors.initials: B
authors.lastname: Oliva
authors.forename: Jordi
authors.initials: J
authors.lastname: Villà-Freixa
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Thomson
mesh_terms: D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D003198:Computer Simulation; D004268:DNA-Binding Proteins; D006801:Humans; D008956:Models, Chemical; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D017354:Point Mutation; D011485:Protein Binding; D054829:RING Finger Domains; D055672:Static Electricity; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; C404508:RNF11 protein, human; D044763:Ubiquitin-Conjugating Enzymes; C105129:RNF103 protein, human; D044767:Ubiquitin-Protein Ligases