Anionic Phospholipids Induce Conformational Changes in Phosphoenolpyruvate Carboxylase to Increase Sensitivity to Cathepsin Proteases.

摘要: Anionic phospholipids induce conformational changes in phosphoenolpyruvate carboxylase to increase sensitivity cathepsin proteases. Jacinto Gandullo1, Jose-Antonio Monreal1, Rosario Alvarez 1; Isabel Diaz2, Sofia Garcia-Maurino1, Cristina Echevarria1*. 1Departamento de Biologia Vegetal, Facultad Biologia, Universidad Sevilla, Seville, Spain. 2 Centro Biotecnologia y Genomica Plantas, Politecnica Madrid, Campus Montegancedo, Pozuelo Alarcon, * Correspondence: Echevarria echeva@us.es Word count: 8780 Number of figures: 6 Keywords: Phosphoenolpyruvate carboxylase, phospholipids, phosphatidic acid, proteolysis, changes, proteases, sorghum. Article type: Original Research 1. Abstract (PEPC) is a cytosolic, homotetrameric enzyme that serves variety functions plants, acting as the primary form CO2 fixation C4 photosynthesis pathway (C4-PEPC). In previous work we have shown C4-PEPC bind anionic resulting PEPC inactivation. Also, showed can associated with membranes and be partially proteolyzed. However, mechanism controlling this remains unknown. Using semi purified-PEPC from sorghum leaf panel PEPC-specific antibodies, analyzed structural induced by cause inactivation enzyme. Conformational observed involved exposure C-terminus native, active conformation. Investigation protease activity demonstrated cysteine proteases co-purify enzyme, protease-specific substrates revealing B L major species present. The phospholipid-induced C-terminal exposed conformation appeared highly sensitive identified initial proteolysis beginning at N-terminus. Taken together, these data provide first evidence promote not only but also its proteolysis.