条斑紫菜叶绿体甘油醛-3-磷酸脱氢酶的cDNA克隆和序列分析

利用已知甘油醛-3-磷酸脱氢酶(GAPDH)的特征性保守区域合成探针,并对条斑紫菜cDNA文库进行筛选,获得了一个编码叶绿体甘油醛-3-磷酸脱氢酶(GapA)的全长cDNA克隆(GAP4)。GAP4包含了全长的叶绿体甘油醛-3-磷酸脱氢酶的cDNA序列,编码72个氨基酸的信号肽和338个氨基酸的成熟蛋白。将获得的GapA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GapA氨基酸序列都包含了4个高度保守的结构域。条斑紫菜GapA的cDNA序列中GC含量很高(64.2％),与紫菜EST分析中得到的结果(65.2％)近似。通过GAPDH的分子系统发育分析,对红藻的分类地位进行了初步探讨。条斑紫菜叶绿体甘油醛-3-磷酸脱氢酶的cDNA序列已登记到GenBank数据库,序列号为:AY273819。

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

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 chloroplast glyceradehyde-3-phosphate dehydrogenase ( GapA). Clone GAP4 contains the complete chloroplast-GAPDH cDNA of P. yezoensis, corresponding to a 72 amino-acid transit peptide and a 338 amino-acid mature protein. Multiple alignment of the predicted mature chloroplast-GAPDH subunit at amino-acid level clearly shows that four highly conserved regions in GAPDH are present in our cDNA clone. The GC contents of the entire region of the GapA cDNA (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. Sequences of chloroplast- GAPDH cDNA have been deposited in GenBank under accession number AY273819.