Relating Surfactant Properties to Activity and Solubilization of the Human Adenosine A3 Receptor
Bryan W. Berger 1, Roxana Y. García 1, Abraham M. Lenhoff 1, Eric W. Kaler 1 and Clifford R. Robinson 1*
1 University of Delaware
* To whom correspondence should be addressed. E-mail: robinson{at}dbi.udel.edu.
Submitted on August 13, 2004
Revised on October 11, 2004
Accepted on 4 April 2005
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Abstract |
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The effects of various surfactants on the activity and stability of the human adenosine A3 receptor (A3) were investigated. The receptor was expressed using stably transfected HEK293 cells at a concentration of 44 pmol functional receptor per milligram membrane protein and purified using over 40 different non-ionic surfactants. A strong correlation was observed between a surfactant's ability to remove A3 from the membrane and the ability of the surfactant to remove A3 selectively relative to other membrane proteins. The activity of A3 once purified also correlates well with the selectivity of the surfactant used. The effects of varying the surfactant were much stronger than those achieved by including A3 ligands in the purification scheme. Notably, all surfactants that gave optimal efficiency, selectivity and activity all fall within a narrow range of hydrophile-lipophile balance values. This effect may reflect the ability of the surfactant to pack effectively at the hydrophobic transmembrane interface. These findings emphasize the importance of identifying appropriate surfactants for a particular membrane protein, and offer promise for the development of rapid and efficient methods to facilitate membrane protein purification.
Key Words:
G-protein coupled receptors (GPCRs), hydrophile-lipophile balance (HLB), membrane protein purification and stability, non-ionic surfactants, packing parameter
