ジャーナル: Nat Struct Mol Biol / 年: 2022 タイトル: Rhodopsin-bestrophin fusion proteins from unicellular algae form gigantic pentameric ion channels. 著者: Andrey Rozenberg / Igor Kaczmarczyk / Donna Matzov / Johannes Vierock / Takashi Nagata / Masahiro Sugiura / Kota Katayama / Yuma Kawasaki / Masae Konno / Yujiro Nagasaka / Mako Aoyama / ...著者: Andrey Rozenberg / Igor Kaczmarczyk / Donna Matzov / Johannes Vierock / Takashi Nagata / Masahiro Sugiura / Kota Katayama / Yuma Kawasaki / Masae Konno / Yujiro Nagasaka / Mako Aoyama / Ishita Das / Efrat Pahima / Jonathan Church / Suliman Adam / Veniamin A Borin / Ariel Chazan / Sandra Augustin / Jonas Wietek / Julien Dine / Yoav Peleg / Akira Kawanabe / Yuichiro Fujiwara / Ofer Yizhar / Mordechai Sheves / Igor Schapiro / Yuji Furutani / Hideki Kandori / Keiichi Inoue / Peter Hegemann / Oded Béjà / Moran Shalev-Benami / 要旨: Many organisms sense light using rhodopsins, photoreceptive proteins containing a retinal chromophore. Here we report the discovery, structure and biophysical characterization of bestrhodopsins, a ...Many organisms sense light using rhodopsins, photoreceptive proteins containing a retinal chromophore. Here we report the discovery, structure and biophysical characterization of bestrhodopsins, a microbial rhodopsin subfamily from marine unicellular algae, in which one rhodopsin domain of eight transmembrane helices or, more often, two such domains in tandem, are C-terminally fused to a bestrophin channel. Cryo-EM analysis of a rhodopsin-rhodopsin-bestrophin fusion revealed that it forms a pentameric megacomplex (~700 kDa) with five rhodopsin pseudodimers surrounding the channel in the center. Bestrhodopsins are metastable and undergo photoconversion between red- and green-absorbing or green- and UVA-absorbing forms in the different variants. The retinal chromophore, in a unique binding pocket, photoisomerizes from all-trans to 11-cis form. Heterologously expressed bestrhodopsin behaves as a light-modulated anion channel.