D-GLYCERATE 3-KINASE, the last unknown enzyme in the photorespiratory cycle in Arabidopsis, belongs to a novel kinase family
D-GLYCERATE 3-KINASE, the last unknown enzyme in the photorespiratory cycle in Arabidopsis, belongs to a novel kinase family
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DOI：
10.1105/tpc.105.033993
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发表时间：
2005-08-01
期刊：
影响因子：
11.6
通讯作者：
Bauwe, H
中科院分区：
文献类型：
--
作者：
Boldt, R;Edner, C;Bauwe, H
D- GLYCERATE 3- KINASE （GLYK; EC 2.7.1.31）催化光呼吸C(2)循环的结束反应，这是光合C(3)循环不可或缺的辅助代谢途径，使陆地植物能够在含氧大气中生长。除GLYK外，所有其他参与C(2)循环的酶都已知其初级结构，并且编码基因已经确定。我们从拟南芥中纯化了这一缺失的酶，并对其进行了部分测序，并将其鉴定为一个假定的激酶注释单拷贝基因At1g80380。在大肠杆菌中进行外源表达后，证实了该基因产物的特异性催化性能。拟南芥T- DNA插入敲除突变体没有GLYK活性，在正常空气中不存活；然而，它们在CO(2)升高的情况下生长，为C(2)循环的最终步骤的强制性提供了直接证据。新鉴定的GLYK在结构和系统发育上都不同于已知的细菌和动物的甘油激酶。同源酶存在于其他植物、真菌和一些蓝藻中。GLYK活性在真菌和蓝藻中的代谢背景仍有待研究。
D- GLYCERATE 3- KINASE ( GLYK; EC 2.7.1.31) catalyzes the concluding reaction of the photorespiratory C(2) cycle, an indispensable ancillary metabolic pathway to the photosynthetic C(3) cycle that enables land plants to grow in an oxygen-containing atmosphere. Except for GLYK, all other enzymes that contribute to the C(2) cycle are known by their primary structures, and the encoding genes have been identified. We have purified and partially sequenced this yet missing enzyme from Arabidopsis thaliana and identified it as a putative kinase- annotated single- copy gene At1g80380. The exclusive catalytic properties of the gene product were confirmed after heterologous expression in Escherichia coli. Arabidopsis T- DNA insertional knockout mutants show no GLYK activity and are not viable in normal air; however, they grow under elevated CO(2), providing direct evidence of the obligatory nature of the ultimate step of the C(2) cycle. The newly identified GLYK is both structurally and phylogenetically distinct from known glycerate kinases from bacteria and animals. Orthologous enzymes are present in other plants, fungi, and some cyanobacteria. The metabolic context of GLYK activity in fungi and cyanobacteria remains to be investigated.