Bioinformatics Analysis and Functional Prediction of Brucella L7/L12 Protein

目的：通过生物信息学方法对布鲁氏菌L7/L12蛋白的结构与功能进行系统分析。方法：从NCBI数据库中获取L7/L12基因核苷酸序列及其编码蛋白的氨基酸序列信息；使用ProtParam和ProtScale对L7/L12蛋白的理化性质和亲疏水性进行分析；运用SignalP 6.0、TMHMM-2.0和NetPhos-3.1预测信号肽序列、跨膜区结构及磷酸化位点；SOPMA、SWISS-MODEL分别预测L7/L12蛋白的二级和三级结构；ABCpred和SYFPEITHI预测B细胞和T细胞抗原表位；MEGA 11.0对L7/L12蛋白的进化关系进行分析。结果：L7/L12蛋白由124个氨基酸组成，具有稳定疏水特性(亲水性指数0.119)和典型核糖体蛋白特征(α螺旋占比69.35%)，无信号肽与跨膜区，有6个磷酸化位点，二级结构中α-螺旋(Hh) 69.35%、无规则卷曲(Cc)22.58%、β-折叠(Ee) 6.45%和β-转角(Tt) 1.61%，三级结构建模(GMQE = 0.78)显示高保守性。筛选出11个B细胞表位和26个T细胞表位(含7个HLA-A*02:01限制性CTL表位)，L7/L12在布鲁氏菌属内高度保守。结论：生物信息学分析L7/L12蛋白具有良好的抗原优势表位，为布鲁氏菌病防控提供了新的分子靶点。Objective: To systematically analyze the structure and function of Brucella L7/L12 protein using bioinformatics approaches. Methods: The nucleotide sequence of the L7/L12 gene and its encoded amino acid sequence were retrieved from the NCBI database. ProtParam and ProtScale were employed to analyze physicochemical properties and hydrophobicity. SignalP 6.0, TMHMM-2.0, and NetPhos-3.1 predicted signal peptides, transmembrane domains, and phosphorylation sites, respectively. SOPMA and SWISS-MODEL predicted secondary and tertiary structures. ABCpred and SYFPEITHI identified B-cell and T-cell epitopes, while MEGA 11.0 analyzed evolutionary relationships. Results: The L7/L12 protein comprises 124 amino acids, exhibiting stable hydrophobic characteristics (hydrophilicity index: 0.119) and typical ribosomal protein features (α-helix content: 69.35%). It lacks signal peptides and transmembrane domains but contains six phosphorylation sites. Secondary structure analysis revealed 69.35% α-helices (Hh), 22.58% random coils (Cc), 6.45% β-sheets (Ee), and 1.61% β-turns (Tt). Tertiary structure modeling (GMQE = 0.78) demonstrated high conservation. Eleven B-cell epitopes and 26 T-cell epitopes (including seven HLA-A*02:01-restricted CTL epitopes) were identified. L7/L12 showed high conservation within the Brucella genus. Conclusion: Bioinformatics analysis confirms that L7/L12 protein harbors dominant antigenic epitopes, providing a novel molecular target for brucellosis prevention and control.