A purified C-terminally truncated human adenosine A(2A) receptor construct is functionally stable and degradation resistant

• Published in: Protein expression and purification Vol. 74; no. 1; pp. 80 - 87
• Main Authors: Singh, Shweta, Hedley, Diana, Kara, Elodie, Gras, Adrien, Iwata, So, Ruprecht, Jonathan, Strange, Philip G, Byrne, Bernadette
• Format: Journal Article
• Language: English
• Published: United States 01.11.2010
• Subjects: Cell Line; Cholesterol Esters - metabolism; Detergents; Gene Expression; Humans; Protein Stability; Receptor, Adenosine A2A - genetics; Receptor, Adenosine A2A - isolation & purification; Receptor, Adenosine A2A - metabolism; Solubility
• ISSN: 1096-0279
• DOI: 10.1016/j.pep.2010.04.018

Recent high resolution structures of modified G-protein coupled receptors (GPCRs) have provided major insight into the mechanisms of receptor-ligand binding. However understanding of the complete mechanism of GPCR function remains limited. This study characterised C-terminally truncated versions of the human adenosine A(2A) receptor (A(2A)R) with a view to producing protein suitable for structural studies. The constructs terminated at residue A316, removing the intracellular C-terminal tail, or V334, producing a C-terminal tail equivalent in length to that of rhodopsin. Higher levels of functional receptor before and after solubilisation were obtained for both C-terminally truncated constructs compared to the wild-type receptor (WT) as assessed by radioligand binding analysis using [(3)H]ZM241385. The construct which yielded the highest level of functional receptor, V334 A(2A)R, was purified in DDM to high homogeneity with a final yield of 2 mg/L. Binding analysis revealed that the purified receptor had a specific activity of 20.2+/-1.2 nmol/mg, close to the theoretical maximum. Pure V334 A(2A)R was resistant to degradation over 15 days when stored at 4 degrees C or 20 degrees C and showed remarkable functional stability when stored at 4 degrees C, retaining 84% of initial functionality after 30 days. This construct is an excellent candidate for structural studies.