Momma T, Negoro T, Hirano H, Matsumoto A, Udaka K, Fukazawa C
Eur J Biochem. 1985 Jun 18;149(3):491-6. doi: 10.1111/j.1432-1033.1985.tb08951.x.
The complete nucleotide sequence of a cloned cDNA, designated pGA5A4B3822, corresponding to glycinin A5A4B3 mRNA was determined. Analysis of the cDNA insert revealed that it contained 1899 nucleotides of mRNA sequence with a 5'-terminal non-translated region of 31 nucleotides, a signal peptide region corresponding to 23 amino acids, an acidic subunit region (A5) corresponding to 97 amino acids, an acidic subunit region (A4) corresponding to 257 amino acids followed by a basic subunit region (B3) corresponding to 185 amino acids, and a 3'-terminal non-translated region of 182 nucleotides. These results show that the glycinin A4 subunit, which is not found to be linked to a basic subunit via a disulfide bond, is synthesized as a full-sized precursor, i.e. the A5A4B3 subunit complex, from a single mRNA, followed by post-translational processing to generate an intermediary subunit complex (A5-B3), covalently linked by a disulfide bond, and the mature A4 subunit, which may associate with the above subunit complex by non-covalent interactions. From the results obtained by the Chou-Fasman rules we speculated that the two post-translational cleavage sites of this subunit precursor might be processed by the same proteolytic enzyme.
测定了一个克隆的cDNA（命名为pGA5A4B3822）的完整核苷酸序列，该序列对应于大豆球蛋白A5A4B3 mRNA。对cDNA插入片段的分析表明，它包含1899个核苷酸的mRNA序列，其5'端非翻译区有31个核苷酸，一个对应23个氨基酸的信号肽区域，一个对应97个氨基酸的酸性亚基区域（A5），一个对应257个氨基酸的酸性亚基区域（A4），随后是一个对应185个氨基酸的碱性亚基区域（B3），以及一个182个核苷酸的3'端非翻译区。这些结果表明，未发现通过二硫键与碱性亚基相连的大豆球蛋白A4亚基，是从单个mRNA作为全长前体即A5A4B3亚基复合物合成的，随后经过翻译后加工生成通过二硫键共价连接的中间亚基复合物（A5-B3），以及可能通过非共价相互作用与上述亚基复合物结合的成熟A4亚基。根据Chou-Fasman规则获得的结果，我们推测该亚基前体的两个翻译后切割位点可能由同一种蛋白酶加工。
