延边大学农学学报

该研究探究了中华蜜蜂气味受体蛋白Or4(AcerOr4)的序列特征及其在不同组织中的表达模式，旨在为其生物学功能的解析提供关键理论支撑。研究利用ExPASy、SignalP、TMHMM等专业在线分析工具，对AcerOr4蛋白的理化参数、亲疏水性分布、信号肽序列、跨膜拓扑结构、亚细胞定位以及功能结构域等进行预测，并构建了三级结构模型。同时利用荧光定量PCR检测了AcerOr4基因在中华蜜蜂不同组织（头部不含触角、胸部、腹部、足部、翅部及触角）中的相对表达水平。结果显示：AcerOr4蛋白编码314个氨基酸残基，相对分子质量为35 931.39 Da，等电点（isoelectric point, pI）值为5.76，总平均疏水指数为0.44，不稳定指数为40.20，为两性特征不稳定蛋白。AcerOr4蛋白不含信号肽，有4个跨膜结构域，存在1个（53位）O-糖基化位点，2个N-糖基化位点，25个磷酸化位点（13个丝氨酸位点，6个苏氨酸位点，6个酪氨酸位点）。二级结构中α-螺旋占比31.85%，延伸链占比29.94%，无规卷曲占比38.22%；三级结构中无规卷曲占比最高，且在N端和C端分布较为密集。进一步分析发现，AcerOr4基因在不同组织中均有表达，且头部表达量显著高于其他组织（P<0.05）。因此，推测AcerOr4蛋白可能通过与辅助蛋白相互作用形成功能性复合体，其跨膜构象与翻译后修饰网络的协同效应可能是调控中华蜜蜂嗅觉感知功能的关键因素。

This study investigated the sequence characteristics and tissue-specific expression patterns of the Odorant Receptor Protein 4(AcerOr4) in the Chinese honeybee, aiming to provide critical theoretical support for elucidating its biological functions. Using specialized online analysis tools such as ExPASy, SignalP, and TMHMM, the study predicted the physicochemical parameters, hydrophilicity distribution, signal peptide sequence, transmembrane topology, subcellular localization, and functional domains of the AcerOr4 protein, and constructed a tertiary structure model. Simultaneously, quantitative fluorescent PCR was employed to detect the relative expression levels of the AcerOr4 gene in different tissues of the Chinese honeybee(head excluding antennae, thorax, abdomen, legs, wings, and antennae). Results showed the AcerOr4 protein encodes 314 amino acid residues with a relative molecular mass of 35,931.39 Da, an isoelectric point(pI) of 5.76, a total average hydrophobicity index of 0.44, and an instability index of 40.20, classifying it as an amphipathic unstable protein. AcerOr4 protein lacks a signal peptide, possesses 4 transmembrane domains, contains 1 O-glycosylation site(at position 53), 2 N-glycosylation sites, and 25 phosphorylation sites(13 serine sites, 6 threonine sites, 6 tyrosine sites). In its secondary structure, α-helices account for 31.85%, extended chains for 29.94%, and random coils for 38.22%. In the tertiary structure, disordered coils constitute the largest proportion and are densely distributed at both the N-and C-termini. Further analysis revealed that the AcerOr4 gene is expressed in various tissues, with significantly higher expression levels in the head region compared to other tissues(P < 0.05). Therefore, it is speculated that the AcerOr4 protein may form functional complexes through interactions with auxiliary proteins. The synergistic effects of its transmembrane conformation and post-translational modification network may be key factors regulating the olfactory perception function of the Chinese honeybee.