Gautier M F, Aleman M E, Guirao A, Marion D, Joudrier P
Laboratoire de Biochimie et Biologie Moléculaire des Céréales, INRA, Montpellier, France.
Plant Mol Biol. 1994 Apr;25(1):43-57. doi: 10.1007/BF00024197.
From a mid-maturation seed cDNA library we have isolated cDNA clones encoding two Triticum aestivum puroindolines. Puroindoline-a and puroindoline-b, which are 55% similar, are basic, cystine-rich and tryptophan-rich proteins. Puroindolines are synthesized as preproproteins which include N- and C-terminal propeptides which could be involved in their vacuolar localization. The mature proteins have a molecular mass of 13 kDa and a calculated isoelectric point greater than 10. A notable feature of the primary structure of puroindolines is the presence of a tryptophan-rich domain which also contains basic residues. A similar tryptophan-rich domain was found within an oat seed protein and a mammalian antimicrobial peptide. The ten cysteine residues of puroindolines are organized in a cysteine skeleton which shows similarity to the cysteine skeleton of other wheat seed cystine-rich proteins. Northern blot analysis showed that puroindoline genes are specifically expressed in T. aestivum developing seeds. No puroindoline transcripts as well as no related genes were detected in Triticum durum. The identity of puroindolines to wheat starch-granule associated proteins is discussed as well as the potential role of puroindolines in the plant defence mechanism.
从一个中等成熟度的种子cDNA文库中，我们分离出了编码两种普通小麦麦醇溶蛋白的cDNA克隆。麦醇溶蛋白-a和麦醇溶蛋白-b的相似度为55%，它们是碱性、富含胱氨酸和色氨酸的蛋白质。麦醇溶蛋白以前体蛋白的形式合成，其中包括可能参与其液泡定位的N端和C端前肽。成熟蛋白的分子量为13 kDa，计算得出的等电点大于10。麦醇溶蛋白一级结构的一个显著特征是存在一个富含色氨酸的结构域，该结构域也含有碱性残基。在燕麦种子蛋白和一种哺乳动物抗菌肽中发现了类似的富含色氨酸的结构域。麦醇溶蛋白的十个半胱氨酸残基以半胱氨酸骨架的形式排列，该骨架与其他小麦种子富含胱氨酸的蛋白质的半胱氨酸骨架相似。Northern杂交分析表明，麦醇溶蛋白基因在普通小麦发育中的种子中特异性表达。在硬粒小麦中未检测到麦醇溶蛋白转录本以及相关基因。文中讨论了麦醇溶蛋白与小麦淀粉颗粒相关蛋白的一致性，以及麦醇溶蛋白在植物防御机制中的潜在作用。
