In vivo transport of three radioactive [ 18 F]-fluorinated deoxysucrose analogs by the maize sucrose transporter ZmSUT1
In vivo transport of three radioactive [ 18 F]-fluorinated deoxysucrose analogs by the maize sucrose transporter ZmSUT1
复制标题
玉米蔗糖转运蛋白 ZmSUT1 体内转运三种放射性 [ 18 F]-氟化脱氧蔗糖类似物
DOI：
10.1016/j.plaphy.2017.03.006
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发表时间：
2017
影响因子：
6.5
通讯作者：
Braun, David M.
中科院分区：
文献类型：
--
作者：
Tran, Thu M.;Hampton, Carissa S.;Brossard, Tom W.;Harmata, Michael;Robertson, J. David;Jurisson, Silvia S.;Braun, David M.
蔗糖转运蛋白（SUT）蛋白将蔗糖转运穿过细胞膜;然而，SUT结合蔗糖的机制方面尚未得到很好的解决。蔗糖中的特定羟基参与与SUT蛋白的氢键。我们以前报道过，在蔗糖果糖基部分的C-6′位取代放射性氟-18 [18 F]不会影响玉米（Zea mays）ZmSUT 1蛋白的蔗糖转运。为了确定蔗糖中另外两个位置（果糖基部分中的C-1′或葡萄糖基部分中的C-6）上羟基的18 F取代如何影响蔗糖转运，我们合成了1′-[F18]氟-1 ′-脱氧蔗糖和6-[F18]氟-6-脱氧蔗糖（[18 F]FDS）类似物。每个[18 F]FDS衍生物被独立地引入到野生型orsut 1突变体植物，这是有缺陷的蔗糖韧皮部加载。所有三种（1′-、6′-和6-）[18 F]FDS衍生物均有效且均等地易位，与碳-14 [14 C]标记的蔗糖相似。因此，单独取代蔗糖中这些位置的羟基不会干扰底物识别、结合或膜转运过程，并且这三个位置的羟基对于蔗糖和ZmSUT 1之间的氢键键合不是必需的。与[14 C]-蔗糖检测相比，[18 F]FDS成像具有几个优点。结果表明，1′-[18F]FDS在野生型叶片中的转运速率约为0.90 ± 0.15 m·h-1，在突变体叶片中的转运速率约为0.68 ± 0.25 m·h-1。总的来说，我们的数据表明，[18 F]FDS类似物是探测蔗糖-SUT相互作用和监测植物中蔗糖转运的有价值的工具。
Sucrose transporter (SUT) proteins translocate sucrose across cell membranes; however, mechanistic aspects of sucrose binding by SUTs are not well resolved. Specific hydroxyl groups in sucrose participate in hydrogen bonding with SUT proteins. We previously reported that substituting a radioactive fluorine-18 [18F] at the C-6′ position within the fructosyl moiety of sucrose did not affect sucrose transport by the maize (Zea mays) ZmSUT1 protein. To determine how18F substitution of hydroxyl groups at two other positions within sucrose, the C-1′ in the fructosyl moiety or the C-6 in the glucosyl moiety, impact sucrose transport, we synthesized 1′-[F18]fluoro-1′-deoxysucrose and 6-[F18]fluoro-6-deoxysucrose ([18F]FDS) analogs. Each [18F]FDS derivative was independently introduced into wild-type orsut1mutant plants, which are defective in sucrose phloem loading. All three (1′-, 6′-, and 6-) [18F]FDS derivatives were efficiently and equally translocated, similarly to carbon-14 [14C]-labeled sucrose. Hence, individually replacing the hydroxyl groups at these positions within sucrose does not interfere with substrate recognition, binding, or membrane transport processes, and hydroxyl groups at these three positions are not essential for hydrogen bonding between sucrose and ZmSUT1. [18F]FDS imaging afforded several advantages compared to [14C]-sucrose detection. We calculated that 1′-[18F]FDS was transported at approximately a rate of 0.90 ± 0.15 m.h-1 in wild-type leaves, and at 0.68 ± 0.25 m.h-1 insut1mutant leaves. Collectively, our data indicated that [18F]FDS analogs are valuable tools to probe sucrose-SUT interactions and to monitor sucrose transport in plants.