STRUCTURE AND EXPRESSION OF A COMPLEMENTARY-DNA FOR THE NUCLEAR CODED PRECURSOR OF HUMAN MITOCHONDRIAL ORNITHINE TRANSCARBAMYLASE
STRUCTURE AND EXPRESSION OF A COMPLEMENTARY-DNA FOR THE NUCLEAR CODED PRECURSOR OF HUMAN MITOCHONDRIAL ORNITHINE TRANSCARBAMYLASE
复制标题
DOI：
10.1126/science.6372096
复制
发表时间：
1984-01-01
期刊：
影响因子：
56.9
通讯作者：
ROSENBERG, LE
中科院分区：
文献类型：
--
作者：
HORWICH, AL;FENTON, WA;ROSENBERG, LE
大多数线粒体蛋白质在细胞核中编码，并在游离的细胞质核糖体上翻译为含有氨基末端“前导”序列的较大前体，其在前体被线粒体摄取后被去除。我们根据克隆的互补DNA的核苷酸序列推导出了人类线粒体基质酶--鸟苷酸转氨甲酰基酶（OTC）前体的完整一级结构。OTC的氨基末端前导肽长32个氨基酸，含有4个组氨酸，但不含酸性残基。前导肽从“成熟”蛋白质的切割发生在谷氨酰胺和天冬酰胺残基之间。成熟人OTC的序列类似于大肠杆菌OTC和天冬氨酸转氨甲酰酶亚基的序列。通过将克隆的OTC互补DNA与SV 40（一种动物病毒）调节元件连接并分离培养的HeLa细胞（其通常不表达OTC）来测试其生物活性。OTC亚基的前体和成熟形式都被鉴定;在稳定的转化体中，还检测到酶活性。
Most mitochondrial proteins are encoded in the nucleus and are translated on free cytoplasmic ribosomes as larger precursors containing amino-terminal "leader" sequences, which are removed after the precursors are taken up by mitochondria. We have deduced the complete primary structure of the precursor of a human mitochondrial matrix enzyme, ornithine transcarbamylase (OTC), from the nucleotide sequence of cloned complementary DNA. The amino-terminal leader peptide of OTC is 32 amino acids in length and contains four arginines but no acidic residues. Cleavage of the leader peptide from the "mature" protein occurs between glutamine and asparagine residues. The sequence of mature human OTC resembles that of the subunits of both OTC and aspartate transcarbamylase from Escherichia coli. The biological activity of the cloned OTC complementary DNA was tested by joining it with SV40 (an animal virus) regulatory elements and transfecting cultured HeLa cells, which do not normally express OTC. Both the precursor and mature forms of the OTC subunit were identified; in stable transformants, enzymatic activity was also detected.