Moscow Institute of Physics and Technology, Dolgoprudnyi, Moscow oblast, Russia.
Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.
Dokl Biochem Biophys. 2020 Nov;495(1):342-346. doi: 10.1134/S1607672920060162. Epub 2020 Dec 25.
This work provides the first characteristics of the rhodopsin SpaR from Sphingomonas paucimobilis, aerobic bacteria associated with opportunistic infections. The sequence analysis of SpaR has shown that this protein has unusual DTS motif which has never reported in rhodopsins from Proteobacteria. We report that SpaR operates as an outward proton pump at low pH; however, proton pumping is almost absent at neutral and alkaline pH. The photocycle of this rhodopsin in detergent micelles slows down with an increase in pH because of longer Schiff base reprotonation. Our results show that the novel microbial ion transporter SpaR of interest both as an object for basic research of membrane proteins and as a promising optogenetic tool.
这项工作首次描述了与机会性感染相关的好氧菌——鞘氨醇单胞菌中的视紫红质 SpaR 的特性。SpaR 的序列分析表明，该蛋白具有不寻常的 DTS 基序，这在变形菌门的视紫红质中从未报道过。我们报告说，SpaR 在低 pH 下作为外向质子泵起作用；然而，在中性和碱性 pH 下，质子泵几乎不存在。由于更长的席夫碱再质子化，这种去污剂胶束中的视紫红质光循环随着 pH 的增加而减慢。我们的结果表明，新型微生物离子转运蛋白 SpaR 不仅是膜蛋白基础研究的对象，而且是一种很有前途的光遗传学工具。
