新疆細粒棘球絳蟲EgAgB8/3蛋白的生物信息學分析及意義

馬海梅+吾拉木·馬木提+張峰波+龐盼+趙慧+丁劍冰

[摘要] 目的 分析新疆細粒棘球蚴EgAgB8/3蛋白氨基酸序列，了解該蛋白特性，預測其抗原表位，為進一步研究和選擇包蟲病免疫學診斷與防治的最佳候選抗原提供理論依據。 方法 利用生物信息學方法推測EgAgB8/3蛋白氨基酸序列及理化性質，用不同的生物信息學軟件分析EgAgB8/3蛋白的特性及二級結構，并結合多參數預測其抗原表位。 結果 EgAgB8/3抗原是由75個氨基酸殘基組成的多肽，相對分子質量為8.58×103，等電點為8.5；蛋白特性分析顯示EgAgB8/3蛋白α螺旋、β折疊、β轉角和無規卷曲等二級結構特點，有3個β轉角較好區域可作為表位所在參考區段；3種軟件多參數綜合分析預測，EgAgB8/3蛋白抗原表位集中在1～7（FVVVAHA）、6～19（HADDDDDEVTKTKK）、32～38（FQSDPLG）區段。 結論 運用生物信息學分析方法預測到EgAgB8/3抗原3個B細胞的優勢表位，對進一步研究EgAgB8/3抗原性和研發更有價值的包蟲病免疫診斷與防治靶標具有重要意義。

[關鍵詞] 細粒棘球絳蟲；EgAgB8/3；生物信息學；表位

[中圖分類號] R383.3 [文獻標識碼] A [文章編號] 1673-7210（2017）05（b）-0008-04

[Abstract] Objective To analyze the amino acid sequencing of EgAgB8/3 protein from Echinococcus granulosus in Xinjiang Uygur Autonomous Region， understand the characteristics of this protein， predict the epitope of its antigen， so as to provide theoretical foundation for further studying and selecting the best alternative antigen of immunological diagnosis and prevention of echinococcosis. Methods The amino acid sequencing and physicochemical property of EgAgB8/3 proteins were predicted by bioinformatics method， the characteristics and secondary structure of EgAgB8/3 proteins were analyzed by different bioinformatics software， and its antigenic epitope was predicted combined with multiple parameters. Results EgAgB8/3 antigen was polypeptide composed of 75 amino acid residues， the relative molecular mass was 8.58×103， isoelectric point was 8.5； the analysis of protein characteristics showed the secondary structure characteristics of α-helix， β-sheet， β-turn and random coil of EgAgB8/3 proteins， among which， there were 3 better areas of β-turn that could be as reference segment of epitope； comprehensive analysis of three software and multiple parameters predicted that， the epitope of EgAgB8/3 protein antigen was mainly located in 1-7 （FVVVAHA）， 6-19 （HADDDDDEVTKTKK） and 32-38 （FQSDPLG）. Conclusion The prediction for dominant epitope of three B cell epitopes of EgAgB8/3 protein by bioinformatics method has important significance for further studying the antigenicity of EgAgB8/3 and developing more valuable target for immunological diagnosis and prevention of echinococcosis.

[Key words] Echinococcus granulosus； EgAgB8/3； Bioinformatics； Epitope

細粒棘球蚴所致囊型包蟲病（cystic echinococcosis，CE）是一種嚴重人畜共患寄生蟲病[1]。我國CE流行區主要集中在內蒙古、新疆、青海、西藏、寧夏、四川、甘肅7個省份的牧區，給當地人生命健康、經濟發展和社會和諧穩定帶來嚴重影響。尋找特異性強、敏感性高的候選抗原靶標分子是CE診斷和防治的當務之急。細粒棘球蚴抗原B（Echinococcus granulosus antigen B，EgAgB）是包囊囊液中含量多、免疫原性強、敏感性和特異性高的脂蛋白，為國內外研究熱點[2-5]。EgAgB包括EgAgB8/1、EgAgB8/2、EgAgB8/3、EgAgB8/4、EgAgB8/5等5個約為8 kD的亞單位，各亞單位對不同類型包蟲病診斷的敏感性和特異性效能有明顯差異[6-7]。本課題組前期研究發現，5個亞單位中以EgAgB8/3在細粒棘球絳蟲成蟲階段的表達最為顯著[8-9]，提示其有望成為開發研制包蟲病防治疫苗和診斷試劑最有潛力的后備靶抗原。為進一步探討EgAgB8/3抗原結構特點，本研究用生物信息學方法預測分析其抗原表位，以期為包蟲病診斷防治最佳候選抗原的選擇提供一些理論支撐。

[摘要] 目的 分析新疆細粒棘球蚴EgAgB8/3蛋白氨基酸序列，了解該蛋白特性，預測其抗原表位，為進一步研究和選擇包蟲病免疫學診斷與防治的最佳候選抗原提供理論依據。 方法 利用生物信息學方法推測EgAgB8/3蛋白氨基酸序列及理化性質，用不同的生物信息學軟件分析EgAgB8/3蛋白的特性及二級結構，并結合多參數預測其抗原表位。 結果 EgAgB8/3抗原是由75個氨基酸殘基組成的多肽，相對分子質量為8.58×103，等電點為8.5；蛋白特性分析顯示EgAgB8/3蛋白α螺旋、β折疊、β轉角和無規卷曲等二級結構特點，有3個β轉角較好區域可作為表位所在參考區段；3種軟件多參數綜合分析預測，EgAgB8/3蛋白抗原表位集中在1～7（FVVVAHA）、6～19（HADDDDDEVTKTKK）、32～38（FQSDPLG）區段。 結論 運用生物信息學分析方法預測到EgAgB8/3抗原3個B細胞的優勢表位，對進一步研究EgAgB8/3抗原性和研發更有價值的包蟲病免疫診斷與防治靶標具有重要意義。

[關鍵詞] 細粒棘球絳蟲；EgAgB8/3；生物信息學；表位

[中圖分類號] R383.3 [文獻標識碼] A [文章編號] 1673-7210（2017）05（b）-0008-04

[Abstract] Objective To analyze the amino acid sequencing of EgAgB8/3 protein from Echinococcus granulosus in Xinjiang Uygur Autonomous Region， understand the characteristics of this protein， predict the epitope of its antigen， so as to provide theoretical foundation for further studying and selecting the best alternative antigen of immunological diagnosis and prevention of echinococcosis. Methods The amino acid sequencing and physicochemical property of EgAgB8/3 proteins were predicted by bioinformatics method， the characteristics and secondary structure of EgAgB8/3 proteins were analyzed by different bioinformatics software， and its antigenic epitope was predicted combined with multiple parameters. Results EgAgB8/3 antigen was polypeptide composed of 75 amino acid residues， the relative molecular mass was 8.58×103， isoelectric point was 8.5； the analysis of protein characteristics showed the secondary structure characteristics of α-helix， β-sheet， β-turn and random coil of EgAgB8/3 proteins， among which， there were 3 better areas of β-turn that could be as reference segment of epitope； comprehensive analysis of three software and multiple parameters predicted that， the epitope of EgAgB8/3 protein antigen was mainly located in 1-7 （FVVVAHA）， 6-19 （HADDDDDEVTKTKK） and 32-38 （FQSDPLG）. Conclusion The prediction for dominant epitope of three B cell epitopes of EgAgB8/3 protein by bioinformatics method has important significance for further studying the antigenicity of EgAgB8/3 and developing more valuable target for immunological diagnosis and prevention of echinococcosis.

[Key words] Echinococcus granulosus； EgAgB8/3； Bioinformatics； Epitope

細粒棘球蚴所致囊型包蟲病（cystic echinococcosis，CE）是一種嚴重人畜共患寄生蟲病[1]。我國CE流行區主要集中在內蒙古、新疆、青海、西藏、寧夏、四川、甘肅7個省份的牧區，給當地人生命健康、經濟發展和社會和諧穩定帶來嚴重影響。尋找特異性強、敏感性高的候選抗原靶標分子是CE診斷和防治的當務之急。細粒棘球蚴抗原B（Echinococcus granulosus antigen B，EgAgB）是包囊囊液中含量多、免疫原性強、敏感性和特異性高的脂蛋白，為國內外研究熱點[2-5]。EgAgB包括EgAgB8/1、EgAgB8/2、EgAgB8/3、EgAgB8/4、EgAgB8/5等5個約為8 kD的亞單位，各亞單位對不同類型包蟲病診斷的敏感性和特異性效能有明顯差異[6-7]。本課題組前期研究發現，5個亞單位中以EgAgB8/3在細粒棘球絳蟲成蟲階段的表達最為顯著[8-9]，提示其有望成為開發研制包蟲病防治疫苗和診斷試劑最有潛力的后備靶抗原。為進一步探討EgAgB8/3抗原結構特點，本研究用生物信息學方法預測分析其抗原表位，以期為包蟲病診斷防治最佳候選抗原的選擇提供一些理論支撐。

[摘要] 目的 分析新疆細粒棘球蚴EgAgB8/3蛋白氨基酸序列，了解該蛋白特性，預測其抗原表位，為進一步研究和選擇包蟲病免疫學診斷與防治的最佳候選抗原提供理論依據。 方法 利用生物信息學方法推測EgAgB8/3蛋白氨基酸序列及理化性質，用不同的生物信息學軟件分析EgAgB8/3蛋白的特性及二級結構，并結合多參數預測其抗原表位。 結果 EgAgB8/3抗原是由75個氨基酸殘基組成的多肽，相對分子質量為8.58×103，等電點為8.5；蛋白特性分析顯示EgAgB8/3蛋白α螺旋、β折疊、β轉角和無規卷曲等二級結構特點，有3個β轉角較好區域可作為表位所在參考區段；3種軟件多參數綜合分析預測，EgAgB8/3蛋白抗原表位集中在1～7（FVVVAHA）、6～19（HADDDDDEVTKTKK）、32～38（FQSDPLG）區段。 結論 運用生物信息學分析方法預測到EgAgB8/3抗原3個B細胞的優勢表位，對進一步研究EgAgB8/3抗原性和研發更有價值的包蟲病免疫診斷與防治靶標具有重要意義。

[關鍵詞] 細粒棘球絳蟲；EgAgB8/3；生物信息學；表位

[中圖分類號] R383.3 [文獻標識碼] A [文章編號] 1673-7210（2017）05（b）-0008-04

[Abstract] Objective To analyze the amino acid sequencing of EgAgB8/3 protein from Echinococcus granulosus in Xinjiang Uygur Autonomous Region， understand the characteristics of this protein， predict the epitope of its antigen， so as to provide theoretical foundation for further studying and selecting the best alternative antigen of immunological diagnosis and prevention of echinococcosis. Methods The amino acid sequencing and physicochemical property of EgAgB8/3 proteins were predicted by bioinformatics method， the characteristics and secondary structure of EgAgB8/3 proteins were analyzed by different bioinformatics software， and its antigenic epitope was predicted combined with multiple parameters. Results EgAgB8/3 antigen was polypeptide composed of 75 amino acid residues， the relative molecular mass was 8.58×103， isoelectric point was 8.5； the analysis of protein characteristics showed the secondary structure characteristics of α-helix， β-sheet， β-turn and random coil of EgAgB8/3 proteins， among which， there were 3 better areas of β-turn that could be as reference segment of epitope； comprehensive analysis of three software and multiple parameters predicted that， the epitope of EgAgB8/3 protein antigen was mainly located in 1-7 （FVVVAHA）， 6-19 （HADDDDDEVTKTKK） and 32-38 （FQSDPLG）. Conclusion The prediction for dominant epitope of three B cell epitopes of EgAgB8/3 protein by bioinformatics method has important significance for further studying the antigenicity of EgAgB8/3 and developing more valuable target for immunological diagnosis and prevention of echinococcosis.

[Key words] Echinococcus granulosus； EgAgB8/3； Bioinformatics； Epitope

細粒棘球蚴所致囊型包蟲病（cystic echinococcosis，CE）是一種嚴重人畜共患寄生蟲病[1]。我國CE流行區主要集中在內蒙古、新疆、青海、西藏、寧夏、四川、甘肅7個省份的牧區，給當地人生命健康、經濟發展和社會和諧穩定帶來嚴重影響。尋找特異性強、敏感性高的候選抗原靶標分子是CE診斷和防治的當務之急。細粒棘球蚴抗原B（Echinococcus granulosus antigen B，EgAgB）是包囊囊液中含量多、免疫原性強、敏感性和特異性高的脂蛋白，為國內外研究熱點[2-5]。EgAgB包括EgAgB8/1、EgAgB8/2、EgAgB8/3、EgAgB8/4、EgAgB8/5等5個約為8 kD的亞單位，各亞單位對不同類型包蟲病診斷的敏感性和特異性效能有明顯差異[6-7]。本課題組前期研究發現，5個亞單位中以EgAgB8/3在細粒棘球絳蟲成蟲階段的表達最為顯著[8-9]，提示其有望成為開發研制包蟲病防治疫苗和診斷試劑最有潛力的后備靶抗原。為進一步探討EgAgB8/3抗原結構特點，本研究用生物信息學方法預測分析其抗原表位，以期為包蟲病診斷防治最佳候選抗原的選擇提供一些理論支撐。

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（收稿日期：2017-01-05 本文編輯：張瑜杰）