Identification And Binding Properties Of Odorant-binding Proteins OBP1 And OBP2 Of Platypus Parallelus

Platypus parallelus is one of the most aggressive species in Platypodidae.Studies have shown that it has established its populations in Hainan and has a tendency to become a dominant species of rubber trees,which has major potential harm to important strategic resource rubber trees in China.In order to select behavior control chemicals and research function of P.parallelus odorant binding proteins.In this paper,transcriptomic data of P.parallelus was constructed and odorant binding proteins of P.parallelus was identified and analyzed.The prokaryotic expression,fluorescence competitive binding assay and molecular docking experiment were adopted to provide a theoretical basis for the research and development of the attractant and comprehensive control:1.In total,78 olfactory-related genes were identified from the transcriptome data of P.parallelus,including 39 ORs genes,14 OBPs genes,11 CSPs genes,8 IRs genes and 6SNMPs genes.2.Based on analysis of P.parallelus odorant binding proteins,12 OBPs have full open reading frames,including 7 Classic OBP,3 Minus-C OBP,2 Plus-C OBP.The open reading frame of Ppar OBP1 is 399 bp in length.The signal peptide at the N-terminus was consist of 20 amino acid residues.Ppar OBP1 contains four conserved cysteine sites,which was consistent with the characteristics of Minus-C OBPs.The open reading frame of Ppar OBP2 is 393 bp in length.The signal peptide at the N-terminus was consist of 21 amino acid residues.Ppar OBP2 contains six conserved cysteine sites,which was consistent with the characteristics of Classic OBPs.3.Soluble recombinant protein p ET30a(+)-Ppar OBP1,p ET30a(+)-Ppar OBP2 were induced and expressed by prokaryotic expression.The induction process last 9 h at 28℃with IPTG(0.1 mmol/L)added.4.The results of fluorescence competitive binding assay showed that Ppar OBP1 strong binding with Longifolen.There are strong binding between Ppar OBP2 and Myrcene,α-Pinene.Ppar OBP2 has weakly bind with 2-Methyl-3-buten-2-ol,S-(-)-cis-Verbenol,2-phenyl-2-propanol and Camphene.5.The three dimensional structure of Ppar OBP2 was predicted and structured by SWISS-MODEL.The model was evaluated with many online websites.Molecular docking experiment results show that Ppar OBP2 can bind Myrcene,α-Pinene without H-bond.Hydrophobic amino acid VAL99,ILE102,HIS103 involved in the interaction Ppar OBP2 with two ligands.