De Zaeytijd Jeroen, Van Damme Els J M
Lab Biochemistry and Glycobiology, Department of Molecular Biotechnology, Ghent University, Coupure links 653, B-9000 Ghent, Belgium.
Toxins (Basel). 2017 Mar 29;9(4):123. doi: 10.3390/toxins9040123.
Ribosome-inactivating proteins (RIPs) are a class of cytotoxic enzymes that can depurinate rRNAs thereby inhibiting protein translation. Although these proteins have also been detected in bacteria, fungi, and even some insects, they are especially prevalent in the plant kingdom. This review focuses on the RIPs from cereals. Studies on the taxonomical distribution and evolution of plant RIPs suggest that cereal RIPs have evolved at an enhanced rate giving rise to a large and heterogeneous RIP gene family. Furthermore, several cereal RIP genes are characterized by a unique domain architecture and the lack of a signal peptide. This advanced evolution of cereal RIPs translates into distinct structures, activation mechanisms, and physiological roles. Several cereal RIPs are characterized by activation mechanisms that include the proteolytic removal of internal peptides from the N-glycosidase domain, a feature not documented for non-cereal RIPs. Besides their role in defense against pathogenic fungi or herbivorous insects, cereal RIPs are also involved in endogenous functions such as adaptation to abiotic stress, storage, induction of senescence, and reprogramming of the translational machinery. The unique properties of cereal RIPs are discussed in this review paper.
核糖体失活蛋白（RIPs）是一类细胞毒性酶，可使核糖体RNA脱嘌呤，从而抑制蛋白质翻译。尽管在细菌、真菌甚至一些昆虫中也检测到了这些蛋白质，但它们在植物界尤其普遍。本综述聚焦于谷物中的RIPs。对植物RIPs的分类分布和进化研究表明，谷物RIPs进化速度加快，形成了一个庞大且异质的RIP基因家族。此外，几个谷物RIP基因具有独特的结构域结构且缺乏信号肽。谷物RIPs的这种高级进化转化为独特的结构、激活机制和生理功能。几种谷物RIPs的激活机制包括从N-糖苷酶结构域中蛋白水解去除内部肽段，这一特征在非谷物RIPs中未见报道。除了在抵御致病真菌或食草昆虫方面的作用外，谷物RIPs还参与内源性功能，如适应非生物胁迫、储存、诱导衰老以及翻译机制的重编程。本文讨论了谷物RIPs的独特特性。
