【摘要】 利用细胞质抗坏血酸过氧化物酶(APX)基因部分片段为探针,从条斑紫菜(Porhyrayezoensis)叶状体的cDNA文库中筛选出1种新型的编码APX的全长cDNA克隆。该克隆开放阅读框编码242个氨基酸,与高等植物已知的胞质APX序列相似,同时具有两个特征性的保守区域。推导的氨基酸序列具有与在一种单细胞红藻(Galdieriapartite)中发现的APX B相似的杂交类型结构,这种结构可能是红藻或者非绿色光合生物的APX的重要特征。该cDNA克隆编码区G+C含量达到63 7%,其中密码子的第3位G+C含量高达88 4%。本实验得到的抗坏血酸过氧化物酶基因的cDNA序列已登录到GenBank数据库中,登录序号为:AY282755。更多还原

【Abstract】 Screening of a cDNA library from Porphyra yezoensis with probe based upon cytosolic ascorbate peroxidase (APX,EC 1.11.1.11) genes identified a full-length clone apparently encoding a novel type of ascorbate peroxidase.The clone contained an open reading frame for a protein of 242 amino acids,which exhibited sequence similarity to known cytosolic APX from higher plants and contained two motifs conserved in peroxidases.The deduced amino acid sequence of P.yezoensis APX showed a hybrid-type structure,which was only found previously in an APX-B from a unicellular red alga Galdieria partite,similar to both chloroplastic and cytosolic isoforms of higher plants.It was possible that the hybrid-type structure was an important characteristic of red algal APX.APX cDNA from P.yezoensis showed a high (G+C) content (88.4% in the third-base position and 63.7% total) in the coding region.The nucleotide sequence data reported in this paper will appear in the GenBank database under accession number AY282755.更多还原