Homologous Hevea brasiliensis REF (Hevb1) and SRPP (Hevb3) present different auto-assembling.
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.
CNRS, LCPO, UMR 5629, F-33600 Pessac, France; Univ. Bordeaux, LCPO, UMR 5629, F- 33600 Pessac, France. Electronic address: kberthelot@enscbp.fr.
Karine
K
Berthelot
CNRS, CBMN, UMR 5248, F-33600 Pessac, France; Univ. Bordeaux, CBMN, UMR 5248, F-33600 Pessac, France.
Sophie
S
Lecomte
CNRS, LCPO, UMR 5629, F-33600 Pessac, France; Univ. Bordeaux, LCPO, UMR 5629, F- 33600 Pessac, France.
Yannick
Y
Estevez
Univ. Bordeaux 2, CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France.
Bénédicte
B
Coulary-Salin
CNRS, LCPO, UMR 5629, F-33600 Pessac, France; Univ. Bordeaux, LCPO, UMR 5629, F- 33600 Pessac, France. Electronic address: peruch@enscbp.fr.
Frédéric
F
Peruch
D000371:Agglutination / Q000235:genetics; D000595:Amino Acid Sequence; D000682:Amyloid / Q000235:genetics / Q000378:metabolism; D052179:Antigens, Plant / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D028482:Hevea / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
D000682:Amyloid; D052179:Antigens, Plant; D010940:Plant Proteins; C119716:SRPP protein, Hevea brasiliensis; C061477:REF protein, Hevea brasiliensis
ATR-FTIR; Amyloid; Auto-assembly; DLS; GHS; Hb; Hevea brasiliensis (hevea); PM-IRRAS; Pa; Parthenium argentatum (guayule); Protein aggregation; REF; SRP; SRPP; TEM; Taraxacum brevicorniculatum (dandelion); Tb; attenuated-total reflectance Fourier-transform infra-red; dynamic light scattering; guayule homologue of SRPP; polarization-modulation-infrared reflection-adsorption spectroscopy; rubber elongation factor; small rubber article protein; stress-related protein; transmission electronic microcopy