In Silico Cloning and Characterization of the Glycerol-3-Phosphate Dehydrogenase (GPDH) Gene Family in the Green Microalga Chlamydomonas reinhardtii
In Silico Cloning and Characterization of the Glycerol-3-Phosphate Dehydrogenase (GPDH) Gene Family in the Green Microalga Chlamydomonas reinhardtii
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DOI：
10.1007/s00284-012-0095-6
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发表时间：
2012-05-01
影响因子：
2.6
通讯作者：
Peraza-Echeverria, Santy
中科院分区：
文献类型：
--
作者：
Herrera-Valencia, Virginia A.;Macario-Gonzalez, Laura A.;Peraza-Echeverria, Santy
3-磷酸甘油脱氢酶 (GPDH) 催化磷酸二羟丙酮 (DHAP) 和 NADH 转化为 3-磷酸甘油 (G3P) 和 NAD(+)。 G3P 作为微藻中甘油和甘油脂合成的前体非常重要。此前已从绿色微藻莱茵衣藻中纯化出 GPDH 酶，但之前尚未对编码 GPDH 的基因进行表征。在这项研究中，我们报告了来自莱茵衣藻的三个假定 GPDH 基因的计算机表征：CrGPDH1、CrGPDH2 和 CrGPDH3。这些序列与微藻杜氏盐藻和绿色杜氏藻的 GPDH 基因显着相似。蛋白质三维结构的预测显示了GPDH酶的特征折叠拓扑。此外，系统发育分析表明，这三种 CrGPDH 与杜氏藻的特征性 GPDH 具有相同的进化枝，表明它们具有共同的进化起源和相似的催化功能。此外，这些序列的 K (a)/K (s) 比率表明它们正在接受纯化选择。此外，表达分析显示 CrGPDH1 的组成型表达，而 CrGPDH2 和 CrGPDH3 是响应渗透压而被诱导的，表明这两个序列在甘油合成中可能发挥作用，作为渗透调节中的相容溶质，并且可能也在莱茵衣藻的脂质合成中发挥作用。这项研究为该模型微藻中 GPDH 家族的进一步生化和遗传学研究奠定了基础，也为评估这些基因增强生物柴油生产中 TAG 合成的潜力提供了机会。
Glycerol-3-phosphate dehydrogenase (GPDH) catalyzes the conversion of dihydroxyacetone phosphate (DHAP) and NADH to glycerol-3-phosphate (G3P) and NAD(+). G3P is important as a precursor for glycerol and glycerolipid synthesis in microalgae. A GPDH enzyme has been previously purified from the green microalga Chlamydomonas reinhardtii, however, no genes coding for GPDH have been characterized before. In this study, we report the in silico characterization of three putative GPDH genes from C. reinhardtii: CrGPDH1, CrGPDH2, and CrGPDH3. These sequences showed a significant similarity to characterized GPDH genes from the microalgae Dunaliella salina and Dunaliella viridis. The prediction of the three-dimensional structure of the proteins showed the characteristic fold topology of GPDH enzymes. Furthermore, the phylogenetic analysis showed that the three CrGPDHs share the same clade with characterized GPDHs from Dunaliella suggesting a common evolutionary origin and a similar catalytic function. In addition, the K (a)/K (s) ratios of these sequences suggested that they are under purifying selection. Moreover, the expression analysis showed a constitutive expression of CrGPDH1, while CrGPDH2 and CrGPDH3 were induced in response to osmotic stress, suggesting a possible role for these two sequences in the synthesis of glycerol as a compatible solute in osmoregulation, and perhaps also in lipid synthesis in C. reinhardtii. This study has provided a foundation for further biochemical and genetic studies of the GPDH family in this model microalga, and also opportunities to assess the potential of these genes to enhance the synthesis of TAGs for biodiesel production.