Uptake of adenine by purine permeases of Coffea canephora
Uptake of adenine by purine permeases of Coffea canephora
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DOI：
10.1080/09168451.2019.1606698
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发表时间：
2019-04-20
影响因子：
1.6
通讯作者：
Sugiyama, Akifumi
中科院分区：
文献类型：
--
作者：
Kakegawa, Hirofumi;Shitan, Nobukazu;Sugiyama, Akifumi
嘌呤渗透酶（PUP）介导质子偶联将核苷酸碱基及其衍生物摄取到细胞质中。 PUP 促进腺嘌呤、细胞分裂素和尼古丁的吸收。咖啡因是一种源自黄嘌呤核苷的嘌呤生物碱，仅存在于少数双子叶植物物种中，包括咖啡、可可和茶。尽管咖啡因不是拟南芥和水稻中的内源代谢物，但 AtPUP1 和 OsPUP7 被认为可以转运咖啡因。在这项研究中，我们在 Coffea canephora 基因组中鉴定出了 15 个 PUP。酵母中的直接摄取测量表明，CcPUP1 和 CcPUP5 促进腺嘌呤（但不促进咖啡因）运输。腺嘌呤的吸收具有 pH 依赖性，在 pH 3 和 4 时活性增加，并受到尼日利亚菌素（一种钾质子离子载体）的抑制，表明 CcPUP1 和 CcPUP5 作为质子同向转运蛋白发挥作用。此外，过量的咖啡因不会竞争性地抑制腺嘌呤的摄取，这意味着 C. canephora 的 PUP 已进化为对咖啡因不敏感，以促进腺嘌呤有效摄取到细胞质中。
Purine permeases (PUPs) mediate the proton-coupled uptake of nucleotide bases and their derivatives into cytosol. PUPs facilitate uptake of adenine, cytokinins and nicotine. Caffeine, a purine alkaloid derived from xanthosine, occurs in only a few eudicot species, including coffee, cacao, and tea. Although caffeine is not an endogenous metabolite in Arabidopsis and rice, AtPUP1 and OsPUP7 were suggested to transport caffeine. In this study, we identified 15 PUPs in the genome of Coffea canephora. Direct uptake measurements in yeast demonstrated that CcPUP1 and CcPUP5 facilitate adenine - but not caffeine - transport. Adenine uptake was pH-dependent, with increased activity at pH 3 and 4, and inhibited by nigericin, a potassium-proton ionophore, suggesting that CcPUP1 and CcPUP5 function as proton-symporters. Furthermore, adenine uptake was not competitively inhibited by an excess amount of caffeine, which implies that PUPs of C. canephora have evolved to become caffeine-insensitive to promote efficient uptake of adenine into cytosol.