Interaction between sodium dodecyl sulfate and membrane reconstituted aquaporins: A comparative study of spinach SoPIP2;1 and E. coli AqpZ
| Autor: | Jaume Torres, Ardcharaporn Vararattanavech, Jesper S. Hansen, I Plasencia, Per Jr Greisen, Julie Bomholt, Claus Hélix-Nielsen, Jenny Emnéus |
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| Jazyk: | angličtina |
| Předmět: |
Circular dichroism
Biophysics Aquaporins Micelle Biochemistry Hydrophobic effect Reconstitution chemistry.chemical_compound Spinacia oleracea Lipid membrane Escherichia coli Sodium dodecyl sulfate Lipid bilayer Fluorescent Dyes Chromatography Chemistry Circular Dichroism Aquaporin Folding Cell Biology Transmembrane protein Membrane Spectrometry Fluorescence Critical micelle concentration Membrane protein |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. (10):2600-2607 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/j.bbamem.2011.05.021 |
| Popis: | This study describes the interaction between sodium dodecyl sulfate (SDS) and membrane proteins reconstituted into large unilamellar lipid vesicles and detergent micelles studied by circular dichroism (CD) and polarity sensitive probe labeling. Specifically, we carried out a comparative study of two aquaporins with high structural homology SoPIP2;1 and AqpZ using identical reconstitution conditions. Our CD results indicate that SDS, when added to membrane-reconstituted aquaporins in concentrations below the SDS critical micelle concentration (CMC, ~ 8 mM), causes helical rearrangements of both aquaporins. However, we do not find compelling evidence for unfolding. In contrast when SDS is added to detergent stabilized aquaporins, SoPIP2;1 partly unfolds, while AqpZ secondary structure is unaffected. Using a fluorescent polarity sensitive probe (Badan) we show that SDS action on membrane reconstituted SoPIP2;1 as well as AqpZ is associated with initial increased hydrophobic interactions in protein transmembrane (TM) spanning regions up to a concentration of 0.1× CMC. At higher SDS concentrations TM hydrophobic interactions, as reported by Badan, decrease and reach a plateau from SDS CMC up to 12.5× CMC. Combined, our results show that SDS does not unfold neither SoPIP2;1 nor AqpZ during transition from a membrane reconstituted form to a detergent stabilized state albeit the native folds are changed. |
| Databáze: | OpenAIRE |
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