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

2012; Elsevier BV; Volume: 421; Issue: 3 Linguagem: Inglês

10.1016/j.bbrc.2012.04.036

1090-2104

Antimo Di Maro, Rita Berisio, Alessia Ruggiero, Rachele Tamburino, Valeria Severino, Enza Zacchia, Augusto Parente,

Plant tissue culture and regeneration

PD-S2, type 1 ribosome-inactivating protein from Phytolacca dioica L. seeds, is an N-β-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.