Deciphering the role of adenosine nucleosidases (ADNs) - closing a gap in purine and cytokinin metabolism

解读腺苷核苷酶 (ADN) 的作用 - 缩小嘌呤和细胞分裂素代谢的差距

• 批准号: 102029086
• 负责人: Privatdozent Dr. Klaus von Schwartzenberg
• 金额: --
• 依托单位: Biozentrum Klein Flottbek und Botanischer Garten
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/102029086?language=en
• 关键词: Deciphering; role; adenosine; nucleosidases; ADNs

Adenosine nucleosidase (ADN) is an enzyme of purine metabolism catalyzing the hydrolysis of purine/cytokinin nucleosides to the corresponding bases. Although the activity of this enzyme has been described in several plants, no ADN encoding genes were identified to date. In our preliminary work, we identified the first plant ADN genes (PpADN1, -2 and -3) from the moss Physcomitrella patens as well as from Arabidopsis thaliana (AtADN1 and -2). For the gene product of PpADN1 we proofed the hydrolysis of adenosine and the plant hormone isopentenyladenosine (cytokinin) to the corresponding bases. The project deals with the elucidation of protein properties and the function of ADN in plants using the model organisms Physcomitrella and Arabidopsis. Intensive studies on enzyme kinetics and substrate specificity will be carried out on recombinant ADN proteins. The regulation and substrate inducibility of ADN transcription will be studied in Physcomitrella using RT-PCR. Expression of ADN-GFP fusion proteins in plants will be used to determine the subcellular localisation of ADNs. Further important information will derive from T-DNA insertion mutants of Arabidopsis, which will be analysed for adenosine and cytokinin metabolism. It is aimed to determine in how far ADNs can be used to activate cytokinins by their conversion of low active ribosides to highly active cytokinin bases. Characterisation of ADNs will close a gap in the metabolic pathways of purine/cytokinin interconversion and the expected advances are likely to open applications for crop plant improvement and biotechnology.

腺苷核苷酶(ADN)是一种嘌呤代谢酶，催化嘌呤/细胞分裂素核苷水解为相应的碱基。虽然这种酶在几种植物中的活性已经被描述，但到目前为止还没有发现编码ADN的基因。在我们的初步工作中，我们从苔藓Physcomitrella patens和拟南芥中鉴定了第一个植物ADN基因(PpADN1、-2和-3)(AtADN1和-2)。对于PpADN1的基因产物，我们证明了腺苷和植物激素异戊烯基腺苷(细胞分裂素)被水解成相应的碱基。该项目利用模式生物Physcomitrella和拟南芥来阐明ADN在植物中的蛋白质性质和功能。将对重组ADN蛋白进行深入的酶动力学和底物专一性研究。我们将利用RT-PCR技术来研究ADN转录的调控和底物的诱导作用。ADN-GFP融合蛋白在植物中的表达将被用来确定ADN的亚细胞定位。进一步的重要信息将来自拟南芥的T-DNA插入突变体，这将被分析腺苷和细胞分裂素代谢。目的是确定ADN可以在多大程度上通过将低活性核苷转化为高活性细胞分裂素碱基来激活细胞分裂素。ADN的特性将填补嘌呤/细胞分裂素相互转化代谢途径的空白，预期的进展可能打开作物植物改良和生物技术的应用。