Homologous Hevea brasiliensis REF (Hevb1) and SRPP (Hevb3) present different auto-assembling

Karine Berthelot (1, 2) , Sophie Lecomte (3) , Yannick Estevez (1, 2) , Bénédicte Coulary-Salin (4) , Frédéric Peruch (1, 2)

1 LCPO - Laboratoire de Chimie des Polymères Organiques
2 Team 1 LCPO : Polymerization Catalyses & Engineering
3 CBMN - Chimie et Biologie des Membranes et des Nanoobjets
4 IBGC - Institut de biochimie et génétique cellulaires

HbREF and HbSRPP are two Hevea brasiliensis proteins present on rubber particles, and probably involved in the coagulation of latex. Their function is unclear, but we previously discovered that REF had amyloid properties, which could be of particular interest during the coagulation process. First, we confirmed that REF and SRPP, homologous and principal proteins in hevea latex, are not glycoproteins. In this work, we investigated various aspects of protein interactions: aggregation, auto-assembling, yeast and erythrocyte agglutination, co-interactions by various biochemical (PAGE, spectroscopy, microscopy), biophysical (DLS, ellipsometry) and structural (TEM, ATR-FTIR, PM-IRRAS) approaches. We demonstrated that both proteins are auto-assembling into different aggregative states: REF polymerizes as an amyloid rich in β-sheets and forms quickly large aggregates (> μm), whereas SRPP auto-assembles in solution into stable nanomultimers of a more globular nature. Both proteins are however able to interact together, and SRPP may inhibit the amyloidogenesis of REF. REF is also able to interact with the membranes of yeasts and erythrocytes, leading to their agglutination. In addition, we also showed that both REF and SRPP did not have antimicrobial activity, whereas their activity on membranes has been clearly evidenced. We may suspect that these aggregative properties, even though they are clearly different, may occur during coagulation, when the membrane is destabilized. The interaction of proteins with membranes could help in the colloidal stability of latex, whereas the protein-protein interactions would contribute to the coagulation process, by bringing rubber particles together or eventually disrupting the particle monomembranes.

Mots clés: Amino Acid Sequence; Antigens; Plant; Hevea; Molecular Sequence Data; Phylogeny; Plant Proteins; Protein Binding; Protein Multimerization; Protein Structure; Tertiary; Sequence Homology; Amino Acid; glycoprotein; latex; protein; rubber; rubber elongation factor protein; small rubber particle protein; unclassified drug; antigen antibody reaction; antimicrobial activity; article; erythrocyte; hemagglutination; Hevea brasiliensis; lipid monolayer; priority journal; protein interaction; protein protein interaction; Amyloid; ATR-FTIR; attenuated-total reflectance Fourier-transform infra-red; Auto-assembly; DLS; dynamic light scattering; GHS; guayule homologue of SRPP; Hb; Hevea brasiliensis (hevea); Pa; Parthenium argentatum (guayule); PM-IRRAS; polarization-modulation-infrared reflection-adsorption spectroscopy; Protein aggregation; REF; rubber elongation factor; small rubber article protein; SRP; SRPP; stress-related protein; Taraxacum brevicorniculatum (dandelion); Tb; TEM; transmission electronic microcopy; Agglutination

Domaines: Polymères

Karine Berthelot, Sophie Lecomte, Yannick Estevez, Bénédicte Coulary-Salin, Frédéric Peruch. Homologous Hevea brasiliensis REF (Hevb1) and SRPP (Hevb3) present different auto-assembling. Biochimica et Biophysica Acta Proteins and Proteomics, 2014, 1844 (2), pp.473-485. ⟨10.1016/j.bbapap.2013.10.017⟩. ⟨hal-01368944⟩