Solution structure of the C‐terminal domain of Ole e 9, a major allergen of olive pollen

Abstract

Ole e 9 is an olive pollen allergen belonging to group 2 of pathogenesis-related proteins. The protein is composed of two immunological independent domains: an N-terminal domain (NtD) with 1,3-bglucanase activity, and a C-terminal domain (CtD) that binds 1,3-b-glucans. We have determined the three-dimensional structure of CtD-Ole e 9 (101 amino acids), which consists of two parallel a-helices forming an angle of ;55°, a small antiparallel b-sheet with two short strands, and a 3-10 helix turn, all connected by long coil segments, resembling a novel type of folding among allergens. Two regions surrounded by aromatic residues (F49, Y60, F96, Y91 and Y31, H68, Y65, F78) have been localized on the protein surface, and a role for sugar binding is suggested. The epitope mapping of CtD-Ole e 9 shows that B-cell epitopes are mainly located on loops, although some of them are contained in secondary structural elements. Interestingly, the IgG and IgE epitopes are contiguous or overlapped, rather than coincident. The three-dimensional structure of CtD-Ole e 9 might help to understand the underlying mechanism of its biochemical function and to determine possible structure-allergenicity relationships.

AnArabidopsisGPI-Anchor Plasmodesmal Neck Protein with Callose Binding Activity and Potential to Regulate Cell-to-Cell Trafficking

“…By extrapolation to the OLE-e10 protein, we conclude that it is the X8 domain and not the C-terminal unstructured region that is responsible for callose binding activity. This is supported by the very similar predicted three-dimensional structure of the PDCB1 X8 domain to that of OLE-e9, a probable paralog of the olive OLE-e10 (Barral et al, 2004;Trevino et al, 2008). The subcellular location of PDCB and the callose binding activity points to a role where the N-proximal X8 domain is in a position to interact with callose and, through covalent linkage to GPI, to anchor the plasma membrane to the wall matrix at the neck of the Pds.…”

“…Recently, the three-dimensional structure of the related OLE-e9 protein has been established by nuclear magnetic resonance (Trevino et al, 2008). Using a protein threading algorithm, the putative structure of the PDCB1 X8 domain was compared with the structure of OLE-e9.…”

“…Hence, we also used artificial microRNAs (Schwab et al, 2006) in an attempt to generate transgenic lines with reduced PDCB1 expression. Constructs designed to target two independent sites within the The sequence of the PDCB1 X8 domain was analyzed by threading onto the tertiary structure of OLE-e9 determined by nuclear magnetic resonance (Trevino et al, 2008). The parent OLE-e9 structure is shown in magenta; the PDCB1 X8 domain is shown in gray.…”

Detection and Quantitation of Olive Pollen Allergen Isoforms Using 2-D Western Blotting

“…This glycoprotein displays a molecular weight of 46.4 kDa on 1-D gels and is composed of two immunologically independent domains: an N-terminal domain (NtD) with 1,3-β-glucanase activity, and a C-terminal domain (CtD) that binds 1,3-β-glucans (Treviño et al 2008). The clinical incidence of Ole e 9 is high, affecting the 65% of olive allergic patients.…”

Molecular Mechanisms of Yeast Cell Wall Glucan Remodeling

“…Although alignment between the olive pollen CBM43 domains and that of ScGas2 shows poor sequence conservation (identity of Ϸ17%), six of the GH72 ϩ cysteines appear to be conserved. Very recently, an NMR structure of the C-terminal domain (CTD) of Ole e 9 has become available (39). A superposition with the ScGas2 cysteine-rich domain is relatively poor, giving an r.m.s.d.…”