Pearce G, Moura D S, Stratmann J, Ryan C A
Institute of Biological Chemistry, Washington State University, Pullman, 99164-6340, USA.
Nature. 2001 Jun 14;411(6839):817-20. doi: 10.1038/35081107.
Some animal and yeast hormone genes produce prohormone polypeptides that are proteolytically processed to produce multiple copies of hormones with the same or different functions. In plants, four polypeptides have been identified that can be classed as hormones (intercellular chemical messengers) but none are known to be produced as multiple copies from a single precursor. Here we describe a polyprotein hormone precursor, present in tobacco plants, that gives rise to two polypeptide hormones, as often found in animals and yeast. The tobacco polypeptides activate the synthesis of defensive proteinase-inhibitor proteins in a manner similar to that of systemin, an 18-amino-acid polypeptide found in tomato plants. The two tobacco polypeptides are derived from each end of a 165-amino-acid precursor that bears no homology to tomato prosystemin. The data show that structurally diverse polypeptide hormones in different plant species can serve similar signalling roles, a condition not found in animals or yeast.
一些动物和酵母激素基因产生激素原多肽，这些多肽经蛋白水解加工后可产生具有相同或不同功能的多种激素拷贝。在植物中，已鉴定出四种可归类为激素（细胞间化学信使）的多肽，但尚无已知它们是由单个前体产生多个拷贝的。在此，我们描述了一种存在于烟草植物中的多蛋白激素前体，它能产生两种多肽激素，这在动物和酵母中很常见。烟草多肽以类似于系统素（一种在番茄植物中发现的18个氨基酸的多肽）的方式激活防御性蛋白酶抑制剂蛋白的合成。这两种烟草多肽源自一个165个氨基酸前体的两端，该前体与番茄原系统素无同源性。数据表明，不同植物物种中结构多样的多肽激素可发挥相似的信号传导作用，这在动物或酵母中不存在。
