## 2 Results
### Comparison of Identified Venom-Derived Polypeptides
#### 2.2.7 Major Ant Venom Allergen 2/4-Like (Odorant/Pheromone-Binding Protein-Like)  
This protein was identified from the SDS-PAGE gel bands 10, 11, and 12 (with peptide fragments covering 18% of the full sequence) and from the in-solution proteomic analysis protein 3 (with peptide fragments covering 32% and 31% of the full sequence). It corresponded to the protein product of the _D. quadriceps_ venom gland transcript Contig8_B2-2, Figure S7) that codes for the major ant venom allergen 2/4-like (Odorant/pheromone-binding protein-, OBP/PBP-like). This identified toxin also corresponds to the predicted gene product of a gene segment of the _D. quadriceps_ genome  
Figure 7: Alignment and structural model of cysteine-rich venom protein/major venom allergen 3 from _D. quadriceps_ venom. (**A**) the _D quadriceps_ venom CRISP-, CAP/SCP-like protein was aligned to its hymenoptera homologues. In this alignment, proteins were compared with the predicted protein from the gene segment of _D. quadriceps_ genome [XP_014469499.1] (venom allergen 3-like), venom allergen 3 of _S. invicta_ [VA3_SOLIN] and venom allergen 5 of _V. vulis_ [VA5_VESV]. (**B**) Structure of _D quadriceps_ venom CRISP-, CAP/SCP-like protein that was modelled from the sequence predicted from _D. quadriceps_ venom gland transcript Contig12_B2-2, using as template the crystal structure of the major allergen Sol i 3 from fire ant venom _Solenopsis invicta_ (PDB 2 VZN). The _D. quadriceps_ CRISP-, CAP/SCP-like venom protein was identified by in-gel proteomics (gel band 9), and in-solution proteomics, proteins numbered 1, 8 and 67, which correspond to venom gland transcripts 1_A09_D9_DVA2-1; 1_A09_D9_DVA2; 1_C05_C6_3_DVB1; Consensus TX03; 1_E07_H11_DVC2-1; 1_E07_H11_DVC2; 1_B07_E6_DVC2-1; 1_A09_D9_DVA2-1; 1_A09_D9_DVA2; 1_E06_B4_DVC2-1; 1_E06_B4_DVC2; 1_B03_C4_2_DVC2; 1_C01_H9_3_DVC2. By comparative analysis with the major venom allergen 5 from vespoid wasps, the venom allergen 3 from fire ants and the scoloptooxins from the Thai centipede _Solopendra debanati_, which cause allergic reactions after stinging, this venom-protein in _D. quadriceps_ is presumed to be a potent allergen. [XP_014486970.1]. The theoretical molecular mass predicted for the mature sequence of this 119-aa long peptide is 12,984.28 Da. In Figure 8, the alignment of Venom Allergen 2/4-like (OBP/PBP-like) from the _D. quadriceps_ venom and the venom proteins Sol i 2 and Sol i 4 from _S. invvista_ is shown. Figure 8: Structural analysis of _D. quadriceps_ ant venom allergen 2/4, pheromone/odorant binding protein-like (OBP/PBP). (**A**) Alignment of _D. quadriceps_ OBP/PBP-like and venom proteins Sol i 2 and Sol i 4 from fire ant _S. invvista_. The protein product of _D. quadriceps_ transcript (Contig8_B2-2) expressed ion the venom gland, confirmed by proteomic analysis of the crude venom and the predicted amino acid sequence from the genomic annotation of _D. quadriceps_, XP_014486970.1, as well as the venom allergen 2 (Sol i 2) [VA2_SOLIN] and venom allergen 4 (Sol i 4) [VA4_SOLIN] from _S. invvista_ were aligned. In brown, the leader sequences are shown as predicted by SignalP 5.0. In dark green, natural variants, conflictive or divergent residues are indicated and in light green. In purple, the conserved cysteine residues are highlighted. The solid black lines indicate the pattern of disulfide bonds, as determined for Sol i 2 [VA2_SOLIN]. Amino acid conservation are estimated with the BLOSUM62 matrix. (**B**) Structural model of _D. quadriceps_ venom allergen 2/4, OBP/PBP-like venom protein. The predicted structure was homology modelled from _D. quadriceps_ contig8_B2-2, based on the crystal structure of the venom allergen Sol i 2 from fire ant _S. invvista_ (PDB 2 YGU), as template. This _D.