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Guo Y, Huo J, Bai R, Zhang J, Yao J, Ma K, Zhang Z, Li H, Zhang C. The effects of free Cys residues on the structure, activity, and tetrameric stability of mammalian uricase. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12597-y. [PMID: 37256327 DOI: 10.1007/s00253-023-12597-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 05/04/2023] [Accepted: 05/10/2023] [Indexed: 06/01/2023]
Abstract
Mammalian uricases contain four conserved cysteine (Cys) residues, but little is known about their structures and functions. In this study, we first confirmed that all four Cys residues are free and not involved in disulfide bond formation, using canine uricase as a model protein. Cys residues had a greater effect on stability than on activity based on single Cys-to-Ser (serine) substitutions. Circular dichroism (CD) and homology modeling indicated that C188S reduces β-sheet contents and inter- and intra-subunit hydrophobic interaction, potentially impairing the core tetrameric β-barrel structure of the tunneling-fold protein, and ultimately decreased the tetrameric stability. Additionally, the inactivation of C188S during the stability tests may be a complex process involving depolymerization followed by irregular aggregation. Double mutations or thiol blockage of Cys188 and Cys195 significantly disrupted the formation and stability of tetrameric uricase, which may be mediated by the free thiols in Cys residues. The present results demonstrated that the free Cys residues are essential for tetrameric formation and stability in mammalian uricase. This implies that free cysteine residues, although not involved in disulfide bonding, may play important structural roles in certain proteins, underscoring the significance of the hydrophobic characteristics of the free thiols in Cys residues. KEY POINTS: • Four Cys residues are not involved in disulfide bonding in mammalian uricase. • The hydrophobicity of free thiols is critical for tetrameric stability in uricase. • Free Cys residues can serve structural roles without involving in disulfide bonds.
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Affiliation(s)
- Yong Guo
- College of Pharmacy, Linyi University, Linyi, 276000, Shandong, People's Republic of China
| | - Jingjing Huo
- College of Pharmacy, Linyi University, Linyi, 276000, Shandong, People's Republic of China
| | - Runchao Bai
- Shandong Center for Food and Drug Evaluation & Inspection, Jinan, 250022, Shandong, People's Republic of China
| | - Jingyuan Zhang
- College of Pharmacy, Linyi University, Linyi, 276000, Shandong, People's Republic of China
| | - Jipeng Yao
- College of Pharmacy, Linyi University, Linyi, 276000, Shandong, People's Republic of China
| | - Kaijie Ma
- College of Pharmacy, Linyi University, Linyi, 276000, Shandong, People's Republic of China
| | - Zengtao Zhang
- Renrui Biotechnology Inc., Rizhao, 276599, Shandong, People's Republic of China
| | - Haigang Li
- College of Pharmacy, Linyi University, Linyi, 276000, Shandong, People's Republic of China.
| | - Chun Zhang
- College of Pharmacy, Linyi University, Linyi, 276000, Shandong, People's Republic of China.
- Renrui Biotechnology Inc., Rizhao, 276599, Shandong, People's Republic of China.
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Manning MC, Liu J, Li T, Holcomb RE. Rational Design of Liquid Formulations of Proteins. THERAPEUTIC PROTEINS AND PEPTIDES 2018; 112:1-59. [DOI: 10.1016/bs.apcsb.2018.01.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Tao L, Li D, Li Y, Shi X, Wang J, Rao C, Zhang Y. Designing a mutant Candida uricase with improved polymerization state and enzymatic activity. Protein Eng Des Sel 2017; 30:753-759. [PMID: 29161434 DOI: 10.1093/protein/gzx056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/02/2017] [Indexed: 11/12/2022] Open
Abstract
As human uricase has been silenced during evolution, counterparts from other species become an alternative for the treatment of hyperuricemia. Candida uricase is a promising option among them, but its aggregation propensity remains a major obstacle to clinical use. In this study, we designed two mutations according to homology-modeled 3D structure of Candida uricase: Cys249Ser substitution and C-terminal Leu deletion. The wild-type uricase and three mutants containing either or both of the mutations were expressed in Escherichia coli BL21 and validated by mass spectrometry. Size-exclusion chromatography and electrophoresis analysis demonstrated that aggregation was induced by interchain disulfide bonds and could be significantly avoided by Cys249Ser substitution. In combination with Cys249Ser substitution, deletion of Leu increased the enzymatic activity by 8%. Taken together, mutant containing both mutations is chosen as our target protein which is comparatively more suitable for therapeutic use. In addition, homology-modeled 3D structure was proved to be an efficient approach for protein engineering.
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Affiliation(s)
- Lei Tao
- State Key Laboratory of Cancer Biology, Department of Biopharmaceutics, School of Pharmacy, The Fourth Military Medical University, Xi'an, People's Republic of China.,National Institute for Food and Drug Control, Beijing 100050, People's Republic of China
| | - Dandan Li
- National Institute for Food and Drug Control, Beijing 100050, People's Republic of China
| | - Yonghong Li
- National Institute for Food and Drug Control, Beijing 100050, People's Republic of China
| | - Xinchang Shi
- National Institute for Food and Drug Control, Beijing 100050, People's Republic of China
| | - Junzhi Wang
- National Institute for Food and Drug Control, Beijing 100050, People's Republic of China
| | - Chunming Rao
- National Institute for Food and Drug Control, Beijing 100050, People's Republic of China
| | - Yingqi Zhang
- State Key Laboratory of Cancer Biology, Department of Biopharmaceutics, School of Pharmacy, The Fourth Military Medical University, Xi'an, People's Republic of China
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