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Shen JD, Cai X, Wang M, Liu ZQ, Zheng YG. Proposed mechanism for post-translational self-modification of Co-NHase based on Co 2+ diffusion limitation. Biotechnol J 2021; 16:e2100103. [PMID: 34363653 DOI: 10.1002/biot.202100103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 07/14/2021] [Accepted: 07/27/2021] [Indexed: 11/05/2022]
Abstract
BACKGROUND Nitrile hydratase (NHase), was an excellent biocatalyst for the synthesis of amide compounds. NHase was typical heterodimeric metalloprotein, required of the assistance of activator for active expressions. In this work, we found a special Co-NHase HBA from Caldalkalibacillus thermarum, which had the ability of post-translational self-modification and could incorporate Co2+ into the catalytic center in the absence of activator. METHOD AND RESULTS We simulated the movement of Co2+ in silico and established a hypothetical model to predict the Co2+ incorporation efficiency (XCo ) of NHases. According to the simulation results, NHase mutants with different positive charge distribution were constructed. Compared with wild-type, the Co2+ incorporation efficiency of K1 (M10K) was increased by 2.1-fold from 0.36 to 0.76, and the specific activity was increased by 3.2-fold from 136.3 to 432.0 U/mg, while mutant K1H1 (M10K, D11H) and K2H2 (M10K, D11H, E20K, N21H) lost the ability of post-translation self-modification. CONCLUSIONS AND IMPLICATIONS The interactions of positively charged residues near the catalytic center, such as lysine with strong electrostatic repulsive interaction, arginine with weak electrostatic repulsive interaction and histidine with metal affinity, could limit the free diffusion of Co2+ in NHase and affect the efficiency of post-translational self-modification. This work also provided an effective strategy for protein engineering of NHases and other metalloenzymes. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Ji-Dong Shen
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, China.,Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Xue Cai
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, China.,Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Ming Wang
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, China.,Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Zhi-Qiang Liu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, China.,Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Yu-Guo Zheng
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, China.,Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China
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Shen JD, Cai X, Ni YW, Jin LQ, Liu ZQ, Zheng YG. Structural insights into the thermostability mechanism of a nitrile hydratase from Caldalkalibacillus thermarum by comparative molecular dynamics simulation. Proteins 2021; 89:978-987. [PMID: 33749895 DOI: 10.1002/prot.26076] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/19/2021] [Accepted: 03/13/2021] [Indexed: 11/07/2022]
Abstract
Nitrile hydratase (NHase), an excellent bio-catalyst for the synthesis of amide compounds, was composed of two heterologous subunits. A thermoalkaliphilic NHase NHCTA1 (Tm = 71.3°C) obtained by in silico screening in our study exhibited high flexibility of α-subunit but excellent thermostability, as opposed to previous examples. To gain a deeper structural insight into the thermostability of NHCTA1, comparative molecular dynamics simulation of NHCTA1 and reported NHases was carried out. By comparison, we speculated that β-subunit played a key role in adjusting the flexibility of α-subunit and the different conformations of linker in "α5-helix-coil ring" supersecondary structure of β-subunit can affect the interaction between β-subunit and α-subunit. Mutant NHCTA1-α6 C with a random coil linker and mutant NHCTA1-αβγ with a truncated linker were therefore constructed to understand the impact on NHCTA1 thermostability by varying the supersecondary structure. The varied thermostability of NHCTA1-α6 C and NHCTA1-αβγ (Tmα6C = 74.4°C, Tmαβγ = 65.6°C) verified that the flexibility of α-subunit adjusted by β-subunit was relevant to the stability of NHCTA1. This study gained an insight into the NNHCTA1 thermostability by virtual dynamics comparison and experimental studies without crystallization, and this approach could be applied to other industrial-important enzymes.
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Affiliation(s)
- Ji-Dong Shen
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Xue Cai
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Ye-Wen Ni
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Li-Qun Jin
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Zhi-Qiang Liu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Yu-Guo Zheng
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
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The Effect of Dimethyl Sulfoxide on the Lysozyme Unfolding Kinetics, Thermodynamics, and Mechanism. Biomolecules 2019; 9:biom9100547. [PMID: 31569484 PMCID: PMC6843525 DOI: 10.3390/biom9100547] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 02/07/2023] Open
Abstract
The thermal stability of proteins in the presence of organic solvents and the search for ways to increase this stability are important topics in industrial biocatalysis and protein engineering. The denaturation of hen egg-white lysozyme in mixtures of water with dimethyl sulfoxide (DMSO) with a broad range of compositions was studied using a combination of differential scanning calorimetry (DSC), circular dichroism (CD), and spectrofluorimetry techniques. In this study, for the first time, the kinetics of unfolding of lysozyme in DMSO–water mixtures was characterized. In the presence of DMSO, a sharp decrease in near-UV CD and an increase in the fluorescence signal were observed at lower temperatures than the DSC denaturation peak. It was found that differences in the temperatures of the CD and DSC signal changes increase as the content of DMSO increases. Changes in CD and fluorescence are triggered by a break of the tertiary contacts, leading to an intermediate state, while the DSC peak corresponds to a subsequent complete loss of the native structure. In this way, the commonly used two-state model was proven to be unsuitable to describe the unfolding of lysozyme in the presence of DMSO. In kinetic studies, it was found that even high concentrations of DMSO do not drastically change the activation energy of the initial stage of unfolding associated with a disruption of the tertiary structure, while the enthalpy of denaturation shows a significant dependence on DMSO content. This observation suggests that the structure of the transition state upon unfolding remains similar to the structure of the native state.
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