Making Structural Sense of Dimerization Interfaces of Delta Opioid Receptor Homodimers
| Autor: | Marta Filizola, Davide Provasi, Nevin A. Lambert, Jennifer M. Johnston, Jonathan A. Javitch, Andrea Bortolato, Eneko Urizar, Mahalaxmi Aburi |
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| Rok vydání: | 2011 |
| Předmět: |
Models
Molecular Stereochemistry Dimer Biochemistry Article δ-opioid receptor Mice 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Receptors Opioid delta Animals Humans Protein Structure Quaternary Receptor 030304 developmental biology G protein-coupled receptor 0303 health sciences Chemistry HEK 293 cells Metadynamics Transmembrane protein HEK293 Cells Helix Protein Multimerization 030217 neurology & neurosurgery |
| Zdroj: | Biochemistry |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi101474v |
| Popis: | Opioid receptors, like other members of the G protein-coupled receptor (GPCR) family, have been shown to associate to form dimers and/or oligomers at the plasma membrane. Whether this association is stable or transient is not known. Recent compelling evidence suggests that at least some GPCRs rapidly associate and dissociate. We have recently calculated binding affinities from free energy estimates to predict transient association between mouse delta opioid receptor (DOR) protomers at a symmetric interface involving the fourth transmembrane (TM4) helix (herein termed "4" dimer). Here we present disulfide cross-linking experiments with DOR constructs with cysteines substituted at the extracellular ends of TM4 or TM5 that confirm the formation of DOR complexes involving these helices. Our results are consistent with the involvement of TM4 and/or TM5 at the DOR homodimer interface, but possibly with differing association propensities. Coarse-grained (CG) well-tempered metadynamics simulations of two different dimeric arrangements of DOR involving TM4 alone or with TM5 (herein termed "4/5" dimer) in an explicit lipid-water environment confirmed the presence of two structurally and energetically similar configurations of the 4 dimer, as previously assessed by umbrella sampling calculations, and revealed a single energetic minimum of the 4/5 dimer. Additional CG umbrella sampling simulations of the 4/5 dimer indicated that the strength of association between DOR protomers varies depending on the protein region at the interface, with the 4 dimer being more stable than the 4/5 dimer. |
| Databáze: | OpenAIRE |
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