Department of Biological Science, Faculty of Science, Shizuoka University, Suruga-ku, Shizuoka, Japan.
Department of Life Sciences (Biology), Graduate School of Arts and Sciences, University of Tokyo, Meguro, Tokyo, Japan.
Photochem Photobiol. 2017 May;93(3):903-906. doi: 10.1111/php.12764.
This article highlights the paper by Rockwell et al. in the current issue of Photochemistry and Photobiology. Rockwell et al. describe the discovery of novel two-Cys photocycles within the "expanded red/green" (XRG) cyanobacteriochrome (CBCR) lineage. Comprehensive phylogenetic analysis revealed that several XRG CBCRs possess a second Cys residue in the DXCF (Asp-Xaa-Cys-Phe) motif conserved among the DXCF CBCR lineage. Spectral studies identified that these CBCRs showed green/blue or ultraviolet/blue reversible photoconversion abilities. The green/blue reversible photocycle had not been reported previously among the XRG CBCR lineage. Based on these findings, Rockwell et al. replaced three amino acid residues in a red/green reversible CBCR, NpR6012g4, and succeeded in constructing a violet/green reversible photocycle. These findings, together with previous studies, provide a good explanation for the evolutionary flexibility of the XRG CBCRs.
本文重点介绍了罗克韦尔等人在本期《光化学与光生物学》上发表的论文。罗克韦尔等人在“扩展的红/绿”（XRG）细菌视紫红质（CBCR）谱系中发现了新的双半胱氨酸光循环。全面的系统发育分析表明，几个 XRG CBCR 在 DXCF（天冬氨酸-氨基酸-半胱氨酸-苯丙氨酸）基序中具有第二个半胱氨酸残基，该基序在 DXCF CBCR 谱系中保守。光谱研究表明，这些 CBCR 表现出绿色/蓝色或紫外线/蓝色可逆光致变色能力。在 XRG CBCR 谱系中，以前尚未报道过绿色/蓝色可逆光循环。基于这些发现，罗克韦尔等人在一个红/绿可逆 CBCR，NpR6012g4 中替换了三个氨基酸残基，并成功构建了一个紫/绿可逆光循环。这些发现与以前的研究一起，很好地解释了 XRG CBCR 的进化灵活性。
