X-ray Crystallographic and Fluorometric Analysis of the Interactions of Rhein to Human Serum Albumin

Authors

  • Mei Li,

    1. College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan, China
    2. State Key Laboratory Cultivation Base for the Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Science and Technology of China, Guangxi Normal University, Guilin, Guangxi, China
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  • Philbert Lee,

    1. Ben May Department for Cancer Research, University of Chicago, Chicago, IL, USA
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  • Yao Zhang,

    1. State Key Laboratory Cultivation Base for the Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Science and Technology of China, Guangxi Normal University, Guilin, Guangxi, China
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  • ZhiYuan Ma,

    1. State Key Laboratory Cultivation Base for the Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Science and Technology of China, Guangxi Normal University, Guilin, Guangxi, China
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  • Feng Yang,

    Corresponding author
    1. State Key Laboratory Cultivation Base for the Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Science and Technology of China, Guangxi Normal University, Guilin, Guangxi, China
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  • ZuPing Zhou,

    1. State Key Laboratory Cultivation Base for the Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Science and Technology of China, Guangxi Normal University, Guilin, Guangxi, China
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  • XiaoYang Wu,

    1. Ben May Department for Cancer Research, University of Chicago, Chicago, IL, USA
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  • Hong Liang

    Corresponding author
    1. College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan, China
    2. State Key Laboratory Cultivation Base for the Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Science and Technology of China, Guangxi Normal University, Guilin, Guangxi, China
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Abstract

To investigate the interactions between natural drugs and human serum albumin (HSA), we performed fluorescence spectroscopy and X-ray crystallography to gain insight into binding mechanism and behaviour of rhein to HSA. Our fluorescence results demonstrated that rhein strongly binds with HSA, and other compounds may affect binding affinity of rhein to different extent. Structural analysis revealed that rhein binds to the IIA subdomain of HSA. The carboxylate group of rhein forms hydrogen bonds with Arg218 and Lys199, as well as a salt bond with Arg222. Hydroxyl group (4) of rhein forms a hydrogen bond with His242, and hydroxyl group (5) of rhein forms a hydrogen bond with Arg257. Oxygen atom (7) of rhein forms a hydrogen bond with Arg222, and oxygen atom (6) of rhein forms a hydrogen bond with H2O. Furthermore, hydroxyl group (4) of rhein also forms a hydrogen bond with H2O. Our results reveal the biochemical and structural characteristics of the interaction between rhein and HSA, providing guidance for future development of rhein-based compounds and a drug–HSA delivery system.

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