羊种布鲁氏菌BP26蛋白的生物信息学分析

Bioinformatic analysis of the BP26 protein of Brucella melitensis

目的采用生物信息学方法预测羊种布鲁氏菌BP26蛋白的抗原表位。方法从NCBI数据库中获取羊布鲁氏菌的BP26蛋白的氨基酸序列,利用ExPASy蛋白分析在线软件ProtParam、SOPMA、SWISS MODEL、ProtScale、Signal 5.0、TMHMM 2.0、PSOTR,分析BP26蛋白的理化性质,二、三级结构,亲、疏水性,信号肽,跨膜区及亚细胞定位;使用IEDB分析BP26蛋白的B细胞表位;使用PROSITE SCAN分别BP26蛋白的结构域分析。结果BP26蛋白由250个氨基酸组成,分子式为C1152H1898N328O364S12,相对分子质量为26.5×10^3,理论等电点为6.39,不稳定系数为27.93,为稳定蛋白。二级结构以α-螺旋为主,占41.2%;无规卷曲占36.8%,延伸链占17.2%;β-转角占4.8%。预测其三级结构与同源模板S19株BP26蛋白相似性99.55%,16个BP26分子形成一个新颖的通道状结构。BP26蛋白存在1个跨膜区,该跨膜区域位于7-29位氨基酸,可能为信号肽,与信号肽分析结果一致。Signal 5.0分析BP26蛋白在7-29位氨基酸有一个分泌型蛋白信号肽。BP26蛋白包含有14个线性表位,其中以27-42、108-125、224-240位氨基酸区段为BP26蛋白的优势抗原表位区段。BP26蛋白包含2个N-糖基化位点,2个蛋白激酶C磷酸化作用位点,2个酪蛋白激酶Ⅱ磷酸化作用位点,5个N-豆蔻酰基化位点;亚细胞定位分析BP26蛋白为膜周质蛋白。结论生物信息学分析羊种布鲁氏菌BP26蛋白存在多个B细胞抗原表位,可以作为布鲁氏菌诊断和疫苗研究的候选抗原。

Objective To use bioinformatics to predict the epitope of the BP26 protein of Brucella melitensis.Methods The amino acid sequence of the BP26 protein of B.melitensis was obtained from the NCBI database.The online software ProtParam,SOPMA,SWISS MODEL,ProtScale,Signal 5.0,TMHMM 2.0,and PSOTR were respectively used to predict the physicochemical properties,secondary structure,tertiary structure,hydrophilicity,signal peptides,transmembrane regions,and cell localization of BP26.The online software IEDB was used to predict B-cell epitopes of the BP26 protein,and PROSITE SCAN was used to predict domains of BP26.Results The BP26 protein consisted of 250 amino acids.Its molecular formula was:C1152 H1898 N328 O364 S12,its molecular weight was 26.5×10^3,its theoretical isoelectric point was 6.39,and th itse coefficient of instability was 27.93.It was a stable protein.The protein’s secondary structure mainly consists ofα-helices(41.2%),random coils(36.8%),extended chains(17.2%),andβ-turns(4.8%).Prediction of the tertiary structure indicated a 99.55%similarity to the homologous BP26 protein of the template S19 strain.Results indicated that 16 BP26 molecules form a novel channel-like structure.The BP26 protein has a transmembrane region located at amino acids 7-29,which may be a signal peptide,and this finding is consistent with the results of signal peptide analysis.Signal 5.0 analysis indicated that the BP26 protein has a secreted protein signal peptide at amino acids 7-29.The BP26 protein contains 14 linear epitopes.Amino acids 27-42,amino acids 108-125,and amino acids 224-240 are the dominant epitope segments of the BP26 protein.The BP26 protein contains 2 N-glycosylation sites,2 protein kinase C phosphorylation sites,2 casein kinase II phosphorylation sites,and 5 N-myristoylation sites.Subcellular localization analysis predicted that the BP26 protein is a periplasmic protein.Conclusion There are multiple B-cell epitopes in the BP26 protein,which can be used as an antigens for research on Brucella peptide epitope vaccines.