Structural and enzymatic properties of an in vivo proteolytic form of PD-S2, type 1 ribosome-inactivating protein from seeds of Phytolacca dioica L.

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• 作者：Antimo Di Maro^a ; ^{antimo.dimaro@unina2.it} ; Rita Berisio^b ; Alessia Ruggiero^b ; Rachele Tamburino^a ; Valeria Severino^a ; Enza Zacchia^a ; Augusto Parente^a
• 关键词：2-Me ; 2-尾-mercaptoethanol ; DTT ; dithiothreitol ; Gdn  ; · ;   ; Cl ; guanidinium chloride ; hsDNA ; herring sperm DNA ; PD-S2 ; major form of ribosome-inactivating proteins from seeds of P. dioica
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2012
• 期刊代码：159_0006291x
• 类别：bio
• 出版时间：11 May, 2012
• 卷：421
• 期：3
• 页码：514-520
• 文件大小：768 K

摘要

PD-S2, type 1 ribosome-inactivating protein from Phytolacca dioica L. seeds, is an N-尾-glycosidase likely involved in plant defence. In this work, we purified and characterized an in vivo proteolytic form of PD-S2, named cutPD-S2. Spectroscopic characterization of cutPD-S2 showed that the proteolytic cleavage between Asn195 and Arg196 does not alter the protein fold, but significantly affects its thermal stability. Most importantly, the proteolytic cleavage induces a 370-fold decrease of PD-S2 capacity of inhibiting in vitro protein biosynthesis.

Our data catch the turning point from a typical role of PD-S2 as a defence protein to that of supplier of essential amino acids during seedling development.