Influence of Ca2+ on the surface behavior of phosphatidic acid and its mixture with diacylglycerol pyrophosphate at different pHs

MICAELA PEPPINO MARGUTTI; NATALIA WILKE; ANA LAURA VILLASUSO

CHEMISTRY AND PHYSICS OF LIPIDS

ELSEVIER IRELAND LTD

Lugar: Amsterdam ; Año: 2020 vol. 228 p. 1048871 - 1048871

0009-3084

he signaling lipids phosphatidic acid (PA) and diacylglycerol pyrophosphate (DGPP) are involved in regulating the stress response in plants. PA and DGPP are anionic lipids consisting of a negatively charged phosphomonoester or pyrophosphate group attached to diacylglycerol, respectively. Changes in the pH modulate the protonation of their head groups modifying the interaction with other effectors. Here, we examine in a controlled system how the presence of Ca2+ modulates the surface organization of dioleyl diacylglycerol pyrophosphate (DGPP) and its interaction with dioleoyl phosphatidic acid (DOPA) at different pHs. Both lipids formed expanded monolayers at pH 5 and 8. At acid and basic pHs, monolayers formed by DOPA or DGPP became denser when Ca2+ was added to the subphase. At pH 5, Ca2+ also induced an increase of surface potential of both lipids. Conversely, at pH 8 the effects induced by the presence of Ca2+ on the surface potential were reversed. Mixed monolayers of DOPA and DGP