| Popis: |
The styrene–maleic acid (SMA) copolymers enable a detergent-free extraction of membrane proteins from lipid bilayers yielding stable water-soluble nanocontainers with lipid-encased proteins. Here, we demonstrate the ability of the SMA copolymer to extract a complex of interacting membrane proteins from proteoliposomes, namely the archaeal sensory rhodopsin II from Natronomonas pharaonis, NpSRII, in complex with its transducer, NpHtrII. The NpSRII/NpHtrII complexes retained their structural integrity within SMA lipid particles as revealed by diverse biophysical techniques. Pulse electron paramagnetic resonance data showed the SMA-encased NpSRII/NpHtrII complexes as native-like 2[thin space (1/6-em)]:[thin space (1/6-em)]2 dimers with a distance between NpSRII sites 159 according to the “V”-shaped conformation found in a crystal structure. This work was supported by German Research Foundation (DFG, STE640/14), the Federal Ministry of Education and Research of Germany (BMBF, 05K14MPA), the German Academic Exchange Service (DAAD) and the grants from the Russian Science Foundation (14-50-00029 (K. S.)) and the Russian Foundation for Basic Research (RFBR) (Project No. 15-54-12385 (K. S.), 16-02-00248 (P. T.)). We thank J. P. Klare for helpful discussions. https://www.sechenov.ru/science_and_innovation/repo/?PAGEN_1=15#134868 |
