Rubber particle membranes from the Hevea latex contain predominantly two proteins, REF1 and SRPP1 involved in poly(cis-1,4-isoprene) synthesis or rubber quality. The repartition of both proteins on the small or large rubber particles seems to differ, but their role in the irreversible coagulation of the rubber particle is still unknown. In this study we highlighted the different modes of interactions of both recombinant proteins with different classes of lipids extracted from Hevea brasiliensis latex, and defined as phospholipids (PL), glycolipids (GL) and neutral lipids (NL). We combined two biophysical methods, polarization modulated-infrared reflection adsorption spectroscopy (PM-IRRAS) and ellipsometry to elucidate their interactions with monolayers of each class of lipids. REF1 and SRPP1 interactions with native lipids are clearly different; SRPP1 interacts mostly in surface with PI, GL or NL, without modification of its structure. In contrast REF1 inserts deeply in the lipid monolayers with all lipid classes. With NI, REF1 is even able to switch from alpha-helice conformation to beta-sheet structure, as in its aggregated form (amyloid form). Interaction between REF1 and NL may therefore have a specific role in the irreversible coagulation of rubber particles. (C) 2016 Elsevier B.V. All rights reserved.< Leer menos