条斑紫菜细胞质甘油醛-3-磷酸脱氢酶的cDNA克隆和序列分析

cDNA cloning and sequence characterization of the cytosolic glyceradehyde-3-phosphate dehydrogenase from the marine red alga Porphyra yezoensis

利用已知甘油醛 3 磷酸脱氢酶 (GAPDH)的特征性保守区域获得的探针筛选条斑紫菜cDNA文库 ,获得了 1个全长的cDNA克隆GAP2 ,编码细胞质甘油醛 3 磷酸脱氢酶 (GAPC)。其中GAP2cDNA插入片段为15 96bp ,包括一个 10 0 8bp的开放阅读框编码 336个氨基酸的细胞质甘油醛 3 磷酸脱氢酶 (GAPC)蛋白。将获得的GAPC蛋白的氨基酸序列与其它物种的GAPDH序列进行多重序列比较后 ,发现条斑紫菜的GAPC氨基酸序列包含了 4个高度保守的结构域。条斑紫菜GAPC的cDNA序列中GC含量很高 ,为 6 4 .2 % ,与紫菜EST分析中得到的结果 ( 6 5 .2 % )近似。通过GAPDH的分子发育进化分析 ,对红藻的分类地位进行了初步探讨。条斑紫菜的细胞质甘油醛 3 磷酸脱氢酶的cDNA序列已登记到GenBank数据库 ,序列号分别为 :AY2 7382 0。

Screening of a cDNA library from Porphyra yezoensis with probe based upon known glyceradehyde-3-phosphate dehydrogenase (GAPDH) genes identified a full-length clone apparently encoding cytosolic glyceradehyde-3-phosphate dehydrogenase (GAPC). Clone GAP2 with a 1596bp cDNA insert contains an open reading frame of 1008bp encoding a GAPC protein of 336 amino-acid residues. Multiple alignments of the predicted mature cytosolic-GAPDH subunit at amino-acid level clearly show that four highly conserved regions in GAPDH are present in our cDNA clone. The GC contents of the entire region of the GAPC cDNAs (64.2%) were similar to the average GC content (65.2%) which was obtained by Porphyra EST analysis. The position of red algae in phylogenetic trees inferred from GAPDH sequences was discussed. Sequence of cytosolic-GAPDH cDNA has been deposited in GenBank under accession number AY273820.