Altenbach S B, Pearson K W, Meeker G, Staraci L C, Sun S M
Plant Cell Research Institute, Inc., Dublin, CA 94568.
Plant Mol Biol. 1989 Nov;13(5):513-22. doi: 10.1007/BF00027311.
We have constructed a chimeric gene encoding a Brazil nut methionine-rich seed protein which contains 18% methionine. This gene has been transferred to tobacco and expressed in the developing seeds. Tobacco seeds are able to process the methionine-rich protein efficiently from a larger precursor polypeptide of 17 kDa to the 9 kDa and 3 kDa subunits of the mature protein, a procedure which involves three proteolytic cleavage steps in the Brazil nut seed. The accumulation of the methionine-rich protein in the seeds of tobacco results in a significant increase (30%) in the levels of the methionine in the seed proteins of the transgenic plants. Our data indicate that the introduction of a chimeric gene encoding a methionine-rich seed protein into crop plants, particularly legumes whose seeds are deficient in the essential sulfur-containing amino acids, represents a feasible method for improving the nutritional quality of seed proteins.
我们构建了一个嵌合基因，该基因编码一种富含蛋氨酸的巴西坚果种子蛋白，其中蛋氨酸含量为18%。此基因已被转入烟草并在发育中的种子中表达。烟草种子能够有效地将17 kDa的较大前体多肽加工成成熟蛋白的9 kDa和3 kDa亚基，这一过程涉及巴西坚果种子中的三个蛋白水解切割步骤。富含蛋氨酸的蛋白在烟草种子中的积累导致转基因植物种子蛋白中的蛋氨酸水平显著提高（30%）。我们的数据表明，将编码富含蛋氨酸的种子蛋白的嵌合基因导入作物，特别是种子缺乏必需含硫氨基酸的豆类，是提高种子蛋白营养质量的一种可行方法。
