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| 采用SDS研究泥蚶血红蛋白(Tg-HbⅡ)具有过氧化物酶及抗菌活性的结构基础 |
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濮丽丽1, 王诗怡2, 林志华2,3, 王素芳2,3, 包永波2,3
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1.上海海洋大学水产与生命学院, 上海 201306;2.浙江万里学院生物与环境学院, 浙江省水产种质资源高效利用技术研究重点实验室, 浙江 宁波 315100;3.浙江万里学院宁海海洋生物种业研究院, 浙江 宁海 315604
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| 摘要: |
| 泥蚶血红蛋白(Tg-HbⅡ)除了具有携氧功能外,还具有过氧化物酶活性和抗菌活性。本文采用分光光度法、光谱法和分子对接等技术研究了十二烷基硫酸钠(SDS)对Tg-HbⅡ的结构、过氧化物酶活性及抗菌活性的影响,以探讨Tg-HbⅡ具有过氧化物酶活性及抗菌活性的结构基础。研究结果显示,SDS的疏水烷基长链可嵌入到Tg-HbⅡ血红素口袋内部,与近端His104形成氢键,断裂血红素铁与His104的配位键,使Tg-HbⅡ的Soret带吸收峰降低并发生位移;此外,SDS还可与血红素口袋中的氨基酸形成疏水相互作用,改变血红素口袋原有结构,使得部分疏水氨基酸暴露,导致外源荧光强度增强,最大发射波长红移。SDS可以抑制Tg-HbⅡ的过氧化物酶活性,当SDS浓度为2 mmol•L–1时,Tg-HbⅡ的酶活性仅为原来的20%,在琼脂扩散实验中失去对枯草芽孢杆菌的抗菌活性。以上结果表明,SDS通过破坏血红素口袋的内部结构抑制Tg-HbⅡ的过氧化物酶活性,使其失去抗菌活性,血红素疏水口袋是Tg-HbⅡ具有过氧化物酶活性和抗菌活性的关键结构。本研究为进一步研究Tg-HbⅡ的抗菌机理奠定基础。 |
| 关键词: 泥蚶血红蛋白 十二烷基硫酸钠 过氧化物酶活性 抗菌活性 血红素口袋 |
| DOI：10.11759/hykx20220924001 |
| 分类号:Q816 |
| 基金项目:浙江省重点自然科学基金项目(LZ20C190001); 浙江省科技重大专项(2021C02069-7); 宁波市公益研究重点项目(2021S014); 浙江省生物工程重中之重学科项目(CX2021001)和浙江省高校基本科研业务费项目 |
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| Investigation of the structural basis for peroxidase and anti-bacterial activity of hemoglobin from blood clam Tegillarca granosa (Tg-HbⅡ) using sodium dodecyl sulfate |
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PU Lili1, WANG Shiyi2, LIN Zhihua2,3, WANG Sufang2,3, BAO Yongbo2,3
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1.College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China;2.Key Laboratory of Aquatic Germplasm Resources of Zhejiang, College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China;3.Ninghai Marine Biological Seed Industry Research Institute, Zhejiang Wanli University, Ninghai 315604, China
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| Abstract: |
| Hemoglobin Ⅱ from Tegillarca granosa (Tg-HbⅡ) possesses oxygen-carrying capabilities as well as peroxidase and antibacterial activities. In this study, we examined the effects of sodium dodecyl sulfate (SDS) on the structure, peroxidase activity, and antibacterial activity of Tg-HbⅡ using spectrophotometric, spectroscopic, and molecular docking techniques. Moreover, we explored the structural basis of the peroxidase activity of Tg-HbⅡ and its antibacterial activities. The results revealed that the hydrophobic alkyl long chains of SDS could integrate into the heme pocket of Tg-HbII, forming hydrogen bonds with the proximal His104. This interaction resulted in the breaking of the coordination bond between heme iron and His104, leading to a decrease and shift in the Soret band absorption peak of Tg-HbⅡ. Additionally, SDS could form hydrophobic interactions with the amino acids in the heme pocket, inducing alterations in the original structure and exposing some hydrophobic amino acids. This resulted in an enhanced exogenous fluorescence intensity and a redshift of the maximum emission wavelength. SDS demonstrated an inhibitory effect on the peroxidase activity of Tg-HbⅡ. At 2 mmol•L-1 of SDS concentration, the enzymatic activity of Tg-HbⅡ was only 20% of that of the original, and the antibacterial activity against Bacillus subtilis was lost in agar diffusion experiments. These results indicated that SDS inhibited the peroxidase activity of Tg-HbⅡ by disrupting the internal structure of the heme pocket, consequently leading to the loss of its antibacterial activity. The heme hydrophobic pocket emerged as a key structure for the peroxidase and antibacterial activities of Tg-HbⅡ. This study lays the foundation for future studies on the antibacterial mechanism of Tg-HbⅡ. |
| Key words: Tegillarca granosa hemoglobin sodium dodecyl sulfate peroxidase activity antibacterial activity heme pocket |