Nyunoya H, Lusty C J
J Biol Chem. 1984 Aug 10;259(15):9790-8.
The yeast gene CPA1 coding for the small subunit of arginine-specific carbamyl phosphate synthetase has been cloned by complementation of a cpa 1 mutant with a plasmid library of total yeast chromosomal DNA. Two of the plasmids, pJL113/ST4 and pJL113/ST15, contain DNA inserts in opposite orientations with overlapping sequences of 2.6 kilobases. The nucleotide sequence of a 2.2-kilobase region of the DNA insert carrying the CPA1 gene has been determined. The CPA1 gene has been identified to be 1233 nucleotides long and to code for a polypeptide of 411 amino acids with a calculated molecular weight of 45,358. The amino acid sequence encoded in CPA1 is homologous to the recently determined sequence of the small subunit of Escherichia coli carbamyl phosphate synthetase (Piette, J., Nyunoya, H., Lusty, C.J., Cunin, R., Weyens, G., Crabeel, M., Charlier, D., Glandsdorff, N., and Pierard, A. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 4134-4138) over the entire length of the polypeptide chain. Comparison of the amino acid sequences of the small subunits of yeast and E. coli carbamyl phosphate synthetases to the sequences of Component II of anthranilate and p-aminobenzoate synthases suggests that these amidotransferases are evolutionarily related. The most highly conserved region of the yeast and E. coli enzymes includes a cysteine residue previously found to be at the active site of Pseudomonas putida anthranilate synthase Component II (Kawamura, M., Keim, P.S., Goto, Y., Zalkin, H., and Heinrikson, R.L. (1978) J. Biol. Chem. 253, 4659-4668). Based on the observed homologies in the primary sequences of the other amidotransferases examined, we propose a 13-amino acid long sequence to be part of the catalytic domain of this class of enzymes.
编码精氨酸特异性氨甲酰磷酸合成酶小亚基的酵母基因CPA1，已通过用酵母染色体总DNA的质粒文库对cpa 1突变体进行互补而被克隆。其中两个质粒pJL113/ST4和pJL113/ST15，含有方向相反且重叠序列为2.6千碱基的DNA插入片段。已确定携带CPA1基因的DNA插入片段中一个2.2千碱基区域的核苷酸序列。CPA1基因经鉴定长度为1233个核苷酸，编码一个411个氨基酸的多肽，计算分子量为45358。CPA1编码的氨基酸序列在多肽链的全长上与最近确定的大肠杆菌氨甲酰磷酸合成酶小亚基的序列同源（皮埃特，J.，布谷屋，H.，拉斯蒂，C.J.，库宁，R.，韦扬斯，G.，克拉贝尔，M.，沙利耶，D.，格兰兹多夫，N.，和皮拉尔，A.（1984年）美国国家科学院院刊81，4134 - 4138）。将酵母和大肠杆菌氨甲酰磷酸合成酶小亚基的氨基酸序列与邻氨基苯甲酸合酶和对氨基苯甲酸合酶的组分II的序列进行比较表明，这些氨基转移酶在进化上是相关的。酵母和大肠杆菌酶的最高度保守区域包括一个先前发现位于恶臭假单胞菌邻氨基苯甲酸合酶组分II活性位点的半胱氨酸残基（川村，M.，凯姆，P.S.，后藤，Y.，扎尔金，H.，和海因里克森，R.L.（1978年）生物化学杂志253，4659 - 4668）。基于在所研究的其他氨基转移酶一级序列中观察到的同源性，我们提出一个13个氨基酸长的序列是这类酶催化结构域的一部分。
