Niemann-Pick type C2 (NPC2) proteins in arthropods have been extensively differentiated and possibly duplicated according to environmental conditions and are probable to have different functions. The participation of NPC2 proteins in chemical communication in arthropods brings new objectives in environmental-friendly strategies for pest population control. In this study, NPC2 gene in Macrocentrus cingulum (McinNPC2) was newly identified by rapid amplification cDNA ends (RACE) technology. McinNPC2 amino acid sequence alignment with other representative NPC2 annotates to evaluate the highly conserved consensus amino acids, but with odorant binding proteins in M. cingulum show that only one consensus amino acid. Primary six-cysteine structures that are same to odorant binding proteins in M. cingulum were observed in McinNPC2. Phylogenetic analysis of McinNPC2 indicated that the nearest monophyletic group forming one clade with high posterior probability values clusters as Cyphomyrmex costatus (CcosNPC2) whereas the nearest evolutionary relation group as some odorant binding proteins. Moreover, quantitative real-time PCR (qPCR) measurements show that the McinNPC2 gene expression level in various tissues of the female is significantly and ubiquitously higher than in male, whereas the highest expression level in female antennae. We further explore the binding characterization of recombinant McinNPC2 to candidate odor molecules and did the modeling and docking simulations. The results showed ligands binding specificity and docking tests results indicate that β-ionone, an aroma compound commonly found in essential oils, can strongly bind with McinNPC2. In conclusion, we proposed that McinNPC2 may be involved in chemical communication and play roles in perception of plant volatiles.

节肢动物中的尼曼-匹克（Niemann-Pick）型C2（NPC2）蛋白已根据环境条件进行了广泛分化，并可能重复存在，并且可能具有不同的功能。NPC2蛋白参与节肢动物的化学交流带来了有害生物种群控制的环境友好战略的新目标。在这项研究中，在NPC2基因茧扣带（McinNPC2）通过快速扩增cDNA末端（RACE）技术是新发现的。McinNPC2氨基与其他代表NPC2酸序列比对注释来评估在高度保守的共有氨基酸，但与加臭剂的结合蛋白M.扣带表明只有一个共有氨基酸。是相同的，以气味结合蛋白在原代六半胱氨酸结构M.扣带在McinNPC2观察。对McinNPC2的系统发育分析表明，最近的一元群体形成一个具有高后验概率值的进化枝簇状为Cyphomyrmex costatus。（CcosNPC2），而最接近的进化关系群是一些气味结合蛋白。此外，定量实时PCR（qPCR）测量表明，女性的各种组织中的McinNPC2基因表达水平明显且普遍高于男性，而女性触角中的表达水平最高。我们进一步探讨了重组McinNPC2与候选气味分子的结合特性，并进行了建模和对接仿真。结果表明，配体结合特异性和对接试验结果表明，香精油中常见的香气化合物β-紫罗兰酮可以与McinNPC2牢固结合。总之，我们建议McinNPC2可能参与化学通讯并在植物挥发物的感知中发挥作用。