盐生杜氏藻和衣藻双结构域NAD+-GPD基因的生物信息学分析

盐生杜氏藻（Dunaliella salina）是极端耐盐的单细胞真核绿藻，依赖于NAD的3－磷酸甘油脱氢酶（NAD+-GPD）是盐生杜氏藻调渗物质——甘油合成的关键酶.盐生杜氏藻NAD+-GPD基因是第一个被发现含双结构域（SerB和GPD）的GPD基因.而双结构域可能是盐生杜氏藻具有极强耐盐性和快速合成甘油的关键.通过与莱茵衣藻基因组数据库比对，发现莱茵衣藻（Chlamydomonas reinhardtii）中也存在具有SerB和GPD结构域的NAD+-GPD基因序列.在对两个物种NAD+-GPD基因的基因结构、mRNA组成成分、编码蛋白及其理化性质和编码蛋白结构的分析中，发现二者具有较高的相似性.针对目前仅在盐藻和衣藻中发现含SerB和GPD结构域的NAD+-GPD基因这一现象，分别对SerB和GPD结构域同源基因的系统进化进行了分析.

Bioinformatics Analysis of Two-domain NAD+-GPD Genes in Dunaliella salina and Chlamydomonas reinhardtii

Dunaliella salina, which is extreme halotolerant, is an eucaryotic unicellular green alga. In the osmoregulation of Dunaliella salina glycerol plays an important role. And in the glycerol-producting pathway NAD(+)-dependent glycerol 3-phosphate dehydrogenase(NAD+-GPD) is a key enzyme. It was first found that the NAD+-GPD gene of Dunaliella salina has two domains(SerB and GPD).And having the two domains may be the key reason why Dunaliella salina is extreme halotolerant and has the ability to produce glycerol fast. After comparing the gene with whole genome of Chlamydomonas reinhardtii, another fact was found that the NAD+-GPD genes of Chlamydomonas reinhardtii also have SerB and GPD domains. Then the structures of two-domain NAD+-GPD genes of both organisms, composition of mRNA of the genes, their coding proteins and physical and chemical characteristics of the proteins were analyzed using bioinformatics methods. The structures of the proteins were predicted. And it was found that the genes of both organisms have high similarity. Based on the fact that the two-domain NAD+-GPD genes were only found in Dunaliella salina and Chlamydomonas reinhardtii, phyletic evolutions of both homologous genes of SerB and GPD domains were analysed.