CLONING AND SEQUENCING OF PAPAIN-ENCODING CDNA
CLONING AND SEQUENCING OF PAPAIN-ENCODING CDNA
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DOI：
10.1016/0378-1119(86)90080-6
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发表时间：
1986-01-01
期刊：
影响因子：
3.5
通讯作者：
DIHEL, LC
中科院分区：
文献类型：
--
作者：
COHEN, LW;COGHLAN, VM;DIHEL, LC
从番木瓜果实中提取信使RNA转化为cDNA，克隆到质粒pBR322的PstI酶切位点。测序了约1.4 kb片段的亚克隆。根据木瓜蛋白酶的氨基酸（aa）序列，核苷酸序列与预期相符，但有以下例外：(1)在47、118和135个氨基酸位置发现谷氨酸密码子，而不是谷氨酰胺；(2)在169号a位发现了天冬酰胺密码子，而不是甘氨酸密码子；(3)在aa位86 ~ 88处，观察到aa密码子的顺序不同，即tyr1 -pro-tyr，而不是已发表的pro- tyr1 -tyr。上游序列显示木瓜蛋白酶可能是由一个133-aa前片段合成的，表明该酶是作为无活性酶原合成的。下游片段显示一个不寻常的（AT）9AGAA序列，从双TGA终止密码子开始26 bp。
Messenger RNA extracted from Carica papaya fruit was converted to cDNA and cloned into the PstI restriction site of plasmid pBR322. Subclones of the approximately 1.4-kb fragment were sequenced. The nucleotide sequence matched that expected, based on the amino acid (aa) sequence for papain, with the following exceptions: (1) at aa positions 47, 118 and 135 the codon for glutamate was found instead of glutamine; (2) at aa position 169 the codon for asparagine was found instead of glycine; (3) at aa positions 86-88, a difference in the order of the aa codons was observed, namely tyr-pro-tyr instead of the published pro-tyr-tyr. The upstream sequence revealed that papain is probably synthesized with a 133-aa prosegment, suggesting that the enzyme is synthesized as an inactive zymogen. The downstream segment revealed an unusual (AT)9AGAA sequence beginning 26 bp from the double TGA stop codon.