PORPHOBILINOGEN DEAMINASE IS ENCODED BY A SINGLE-GENE IN ARABIDOPSIS-THALIANA AND IS TARGETED TO THE CHLOROPLASTS
PORPHOBILINOGEN DEAMINASE IS ENCODED BY A SINGLE-GENE IN ARABIDOPSIS-THALIANA AND IS TARGETED TO THE CHLOROPLASTS
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DOI：
10.1007/bf00028854
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发表时间：
1994-11-01
影响因子：
5.1
通讯作者：
SMITH, AG
中科院分区：
文献类型：
--
作者：
LIM, SH;WITTY, M;SMITH, AG
胆色素原脱氨酶（PBG脱氨酶）是叶绿素和血红素合成途径中的早期酶。使用简并寡核苷酸引物，基于来自豌豆的纯化的PBG脱氨酶的氨基酸序列数据，通过PCR从拟南芥基因组DNA扩增片段，然后用于分离来自拟南芥的PBG脱氨酶的cDNA和基因组克隆。该cDNA经引物延伸证实为全长cDNA，编码一个382个残基的前体蛋白，该前体蛋白可被导入分离的叶绿体中并加工成成熟的大小。基因组克隆编码与cDNA相同的序列，除了成熟蛋白质编码区内存在四个内含子和1.7 kb的上游序列。在转录起始点50 bp内没有明显的TATA盒。Southern印迹分析表明，PBG脱氨酶是由一个单一的基因在拟南芥基因组中编码，和RNase保护实验表明，该基因在叶和根中表达。这些结果支持了PBG脱氨酶在所有植物细胞中只有一种形式的结论，它位于质体中。
Porphobilinogen deaminase (PBG deaminase) is an early enzyme of the pathway for chlorophyll and heme synthesis. Using degenerate oligonucleotide primers, based on amino acid sequence data for purified PBG deaminase from pea, a fragment was amplified from Arabidopsis genomic DNA by PCR, and then used to isolate both a cDNA and a genomic clone for PBG deaminase from Arabidopsis. The cDNA, shown to be full-length by primer extension, encodes a precursor protein of 382 residues, which can be imported into isolated chloroplasts and processed to the mature size. The genomic clone encodes an identical sequence to the cDNA, except for the presence of four introns within the coding region of the mature protein, and 1.7 kb of upstream sequence. There is no obvious TATA box within 50 bp of the transcription start. Southern blot analysis suggests that PBG deaminase is encoded by a single gene in the Arabidopsis genome, and RNase protection experiments demonstrated that this gene is expressed in both leaves and roots. These results support the conclusion that there is only one form of PBG deaminase in all plant cells, which is located in the plastid.