幽门螺杆菌CagA基因编码蛋白的生物信息学分析

Bioinformatic analysis of the CagA gene in Helicobacter pylori

目的应用生物信息学软件预测幽门螺杆菌CagA基因编码蛋白的结构和功能。方法从NCBI数据库获取CagA基本的基因信息;应用ProtParam,SignaIP 4.1,TMHMM软件预测CagA基因编码蛋白的理化性质,信号肽和跨膜区;利用在线软件分析蛋白二级结构,建立蛋白三级结构模型。结果 CagA蛋白共1 172个氨基酸,分子式为C5742H9151N1615O1845S13,其中Ala占7.3%,Arg占9.9%,Val占2.8%。负电荷残基(Asp+Glu)162个,正电荷残基(Arg+Lys)167个,分子质量单位为130 747.31,理论等电点为8.42,不稳定性指数18.53,为稳定蛋白;亲水性平均系数为-0.752,可能具有亲水性;二级结构中α螺旋(Hh)602个,占51.37%;延伸链(Ee)147个,占12.54%;β转角(Tt)99个,占8.45%;无规则卷曲(Cc)324个,占27.65%。结论生物信息学分析幽门螺杆菌cagA基因编码蛋白为稳定蛋白且具有亲水性,可为其抗原性研究和高效表位疫苗的研发提供参考,也为胃癌,胃溃疡,十二指肠溃疡的治疗提供了新的靶标。

Objective To use bioinformatic software to predict the structure and function of the protein that CagA of Helicobacter pylori codes for. Methods Basic genetic information on CagA was obtained from the NCBI database.The software ProtParam,SignaIP 4.1,and TMHMM was used to predict the physicochemical properties,the signal peptide,and the transmembrane domain of that protein.The secondary structure of the protein was analyzed,and the tertiary structure of the protein that CagA codes for was modeled using Expasy tools available online. Results CagA protein contains 1172 amino acids.Its molecular formula is C5742 H9151 N1615 O1845 S13,and it consists of Ala（7.3%）,Arg（9.9%）,and Val（2.8%）.The protein has 162 negatively charged residues（Asp＋Glu）and 167 positively charged residues（Arg＋Lys）.Its molecular weight was 130 747.31,its isoelectric point was 8.42,and its instability index was 18.53.The protein is a stable protein,its average hydrophilicity index was-0.752,and the predicted protein is a hydrophobic protein.The secondary structure consisted of 602α-helixes（Hh）,accounting for 51.37% of the structure,99β-turns（Tt）,accounting for 8.45%,147 extended strands（Ee）,accounting for 12.54% and 324 random coils（Cc）,accounting for 27.65%. Conclusion These findings are significant for further studies on the antigenicity of H.pylori cagA and the development of efficient epitope vaccines,and these findings provide a new target for the treatment of gastric cancer,gastric ulcers,and duodenal ulcers.