Ugi Reaction Mediated Detergent Assembly For Membrane Protein Studies

Objective:Membrane proteins（MPs）are the main undertaker of life activities and the target of about 70%of clinical drugs at present.However,due to the amphiphilicity of MPs,its structure and function research lags far behind that of soluble protein.Detergent is a kind of amphiphilic molecule,which can be assembled into micelles to protect MPs from aggregation in aqueous solution.It is an important tool for studying MPs.Suitable detergents are required for the preparation of well solubilized and stabilized MP samples.However,the current detergent categories are far from sufficient for structurally and functionally distinct MPs in different biophysical studies.Therefore,it is highly desired to develop structurally diversified detergents.Methods:With properly pre-loaded functional groups on the various hydrophilic heads,hydrophobic tails,as well as monomeric detergents,dimer detergents were assembled by the mediation of Ugi multi-component reaction.This method expanded great diversity of detergents,from which suitable detergent could be identified for specific proteins.The detergents will be characterized by the physical properties and evaluated by the thermal stabilization of MPs.Result:A series of novel detergents（U-PADs）with two heads and two tails were synthesized.The stabilization capability of U-PADs were comprehensively evaluated on five membrane proteins(A_2AAR,CB2R,GLP-1R,SMO and Msb A)in U-PADs.We found that the preference of detergents was MP dependent.Meanwhile,Mc-23a-Mi was successfully identified and applied to ¹⁹F-NMR study of GLP-1R.Conclusion:These results indicate that the synthetic detergents（U-PADs）preassembled by the Ugi reaction have great potential in the structural study of MPs.