Orientation of Small Multidrug Resistance Transporter Subunits in the Membrane: Correlation with the Positive-Inside Rule
| Autor: | Ramon ter Horst, Juke S. Lolkema, Magdalena A. Kolbusz, Dirk Jan Slotboom |
|---|---|
| Přispěvatelé: | Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology, Enzymology |
| Rok vydání: | 2010 |
| Předmět: |
ATP Binding Cassette Transporter
Subfamily B Protein subunit Green Fluorescent Proteins ATP-binding cassette transporter Biology PROTEIN TOPOLOGY SEQUENCE insertion Cell membrane EBRAB Structural Biology EMRE medicine Molecular Biology Membrane transport protein Escherichia coli Proteins Cell Membrane positive-inside rule Membrane Transport Proteins Alkaline Phosphatase EVOLUTION Transport protein MODEL Protein Subunits ALIGNMENT Crystallography dual topology Dual topology medicine.anatomical_structure Membrane protein ESCHERICHIA-COLI SMR family Biophysics biology.protein Protein topology |
| Zdroj: | Journal of Molecular Biology, 402(1), 127-138. Academic Press |
| ISSN: | 0022-2836 |
| DOI: | 10.1016/j.jmb.2010.07.019 |
| Popis: | Small multidrug resistance (SMR) transport proteins provide a model for the evolution of larger two-domain transport proteins. The orientation in the membrane of 27 proteins from the SMR family was determined using the reporter fusion technique. Nine members were encoded monocistronically (singles) and shown to insert in both orientations (dual topology). Eighteen members were encoded in pairs on the chromosome and shown to insert in fixed orientations; the two proteins in each pair invariably had opposite orientations in the membrane. Interaction between the two proteins in pairs was demonstrated by copurification. The orientation in the membrane of either protein in the pair was affected only marginally by the presence of the other protein.For the proteins in pairs, the orientation in the membrane correlated well with the distribution of positively charges residues (R + K) over the cytoplasmic and extracellular loops (positive-inside rule). In contrast, dual-topology insertion of the singles was predicted less well by the positive-inside rule. Three singles were predicted to insert in a single orientation with the N-terminus and the C-terminus at the extracellular side of the membrane. Analysis of charge distributions suggests the requirement of a threshold number of charges in the cytoplasmic loops for the positive-inside rule to be of predictive value. It is concluded that a combined analysis of gene organization on the chromosome and phylogeny is sufficient to distinguish between fixed or dual topology of SMR members and, probably, similar types of membrane proteins. The positive-inside rule can be used to predict the orientation of members in pairs, but is not suitable as a sole predictor of dual topology. (C) 2010 Elsevier Ltd. All rights reserved. |
| Databáze: | OpenAIRE |
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