The Red-/Green-Switching GAF3 of Cyanobacteriochrome Slr1393 from Synechocystis sp PCC6803 Regulates the Activity of an Adenylyl Cyclase
The Red-/Green-Switching GAF3 of Cyanobacteriochrome Slr1393 from Synechocystis sp PCC6803 Regulates the Activity of an Adenylyl Cyclase
复制标题
来自集胞藻 PCC6803 的蓝细菌色素 Slr1393 的红/绿转换 GAF3 调节腺苷酸环化酶的活性
DOI：
10.1002/cbic.201800323
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发表时间：
2018-09-04
期刊：
影响因子：
3.2
通讯作者：
Zhao, Kai-Hong
中科院分区：
文献类型：
--
作者：
Hu, Ping-Ping;Guo, Rui;Zhao, Kai-Hong
Cyanobacteriochromes (CBCRs) are photoreceptors in cyano-bacteria that present a bilin chromophore-binding GAF domain as a photochromic element to control the activity of a downstream enzyme or regulator. CBCR Slr393 from Synechocystis PCC 6803 carries three GAF domains, but only the third one binds phycocyanobilin covalently. Slr1393 shows photo-chromicity between red and green absorbing states and regulates a C-terminally located histidine kinase. In this work, we fused this third GAF domain to an adenylyl cyclase (AC) from Microcoleus chthonoplostes PCC7420 that in its genuine form is under blue-light control from a LOV domain. A series of RGS-AC variants were constructed with various lengths of the linkers between RGS and AC. Assays in vitro and in living Escherichia coil cells (AC-deletion mutant) demonstrated that the activity of AC was light regulated, namely, the red-light-converted form of RGS Delta 14-Delta 4AC (in vitro) was about three times more active than the green-light-converted form. Expression of the fusion protein RGS Delta 14-Delta 4AC in vivo again showed highest light regulation with at least threefold amplification of the AC function. In some experiments, even tenfold higher activity was observed, which indicated that the protein, if expressed under in vivo conditions, was part of the E. coli physiological conditions and thereby subjected to more complex and variable regulation through other E. coli inherent factors.
