Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Mar 30:12:646084.
doi: 10.3389/fmicb.2021.646084. eCollection 2021.

Characterization and Mechanism of Linearized-Microcystinase Involved in Bacterial Degradation of Microcystins

Jia Wei  1 , Feiyu Huang  1 , Hai Feng  1 , Isaac Yaw Massey  1 , Tezi Clara  1 , Dingxin Long  2 , Yi Cao  2 , Jiayou Luo  1 , Fei Yang  1   2   3
Affiliations

Characterization and Mechanism of Linearized-Microcystinase Involved in Bacterial Degradation of Microcystins

Jia Wei et al. Front Microbiol. .

Abstract

Microcystins (MCs) are extremely hazardous to the ecological environment and public health. How to control and remove MCs is an unsolved problem all over the world. Some microbes and their enzymes are thought to be effective in degrading MCs. Microcystinase can linearize microcystin-leucine-arginine (MC-LR) via a specific locus. However, linearized MC-LR is also very toxic and needs to be removed. How linearized MC-LR was metabolized by linearized-microcystinase, especially how linearized-microcystinase binds to linearized MC-LR, has not been defined. A combination of in vitro experiments and computer simulation was applied to explore the characterization and molecular mechanisms for linearized MC-LR degraded by linearized-microcystinase. The purified linearized-microcystinase was obtained by recombinant Escherichia coli overexpressing. The concentration of linearized MC-LR was detected by high-performance liquid chromatography, and linearized MC-LR degradation products were analyzed by the mass spectrometer. Homology modeling was used to predict the structure of the linearized-microcystinase. Molecular docking techniques on the computer were used to simulate the binding sites of linearized-microcystinase and linearized MC-LR. The purified linearized-microcystinase was obtained successfully. The linearized-microcystinase degraded linearized MC-LR to tetrapeptide efficiently. The second structure of linearized-microcystinase consisted of many alpha-helices, beta-strands, and colis. Linearized-microcystinase interacted the linearized MC-LR with hydrogen bond, hydrophobic interaction, electrostatic forces, and the Van der Waals force. This study firstly reveals the characterization and specific enzymatic mechanism of linearized-microcystinase for catalyzing linearized MC-LR. These findings encourage the application of MC-degrading engineering bacteria and build a great technique for MC-LR biodegradation in environmental engineering.

Keywords: biodegradation; homology modeling; linearized-microcystinase; microcystins; molecular docking.

PubMed Disclaimer

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
A phylogenetic tree based on the linearized-microcystinase sequence.
FIGURE 2
FIGURE 2
Purification and SDS-PAGE of the linearized-microcystinase; 1: pGEX-4T-1; 2: uninduced linearized-microcystinase. 3–5: induce linearized-microcystinase
FIGURE 3
FIGURE 3
HPLC analysis of the degradation of linearized MC-LR incubated with the linearized-microcystinase at time 0 min (A) and 20 min (B).
FIGURE 4
FIGURE 4
HPLC-ESI-MS spectrum in the negative mode and the molecular structure of the product A of linearized MC-LR.
FIGURE 5
FIGURE 5
Homology modeling of linearized-microcystinase (A) and linearized MC-LR (B).
FIGURE 6
FIGURE 6
Docking model of linearized-microcystinase and linearized MC-LR. (A) Overall model of linearized-microcystinase and linearized MC-LR. (B) 3D view of the predicted interactions between linearized-microcystinase and linearized MC-LR. Linearized MC-LR is shown in red, the linearized-microcystinase protein is shown in cyan, whereas the amino acids potentially involved in linearized-microcystinase and linearized MC-LR interaction are shown in green (with orange label). Green, pink, and orange dotted lines indicated the formation of hydrogen bonds, hydrophobic, and electrostatic, respectively. (C) 2D view of the predicted interactions between linearized-microcystinase and linearized MC-LR.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Bourne D. G., Blakeley R. L., Riddles P., Jones G. J. (2006). Biodegradation of the cyanobacterial toxin microcystin LR in natural water and biologically active slow sand filters. Water Res. 40 1294–1302. 10.1016/j.watres.2006.01.022 - DOI - PubMed
    1. Bourne D. G., Jones G. J., Blakeley R. L., Jones A., Negri A. P., Riddles P. (1996). Enzymatic pathway for the bacterial degradation of the cyanobacterial cyclic peptide toxin microcystin LR. Appl. Environ. Microbiol. 62 4086–4094. 10.1128/aem.62.11.4086-4094.1996 - DOI - PMC - PubMed
    1. Bourne D. G., Riddles P., Jones G. J., Smith W., Blakeley R. L. (2001). Characterisation of a gene cluster involved in bacterial degradation of the cyanobacterial toxin microcystin LR. Environ. Toxicol. 16 523–534. 10.1002/tox.10013 - DOI - PubMed
    1. Carmichael W. W., Meriluoto J., Spoof L., Codd G. A. (2018). Handbook of cyanobacterial monitoring and cyanotoxin analysis. Anal. Bioanal. Chem. 410 1405–1406. 10.1007/s00216-017-0804-x - DOI
    1. Chen L., Yang S., Wen C., Zheng S., Yang Y., Feng X., et al. (2019). Regulation of microcystin-LR-induced DNA damage by miR-451a in HL7702 Cells. Toxins (Basel) 11:164. 10.3390/toxins11030164 - DOI - PMC - PubMed

LinkOut - more resources