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14 pages, 5606 KB

Open AccessArticle

Enantioselectivity in Vanadium-Dependent Haloperoxidases of Different Marine Sources for Sulfide Oxidation to Sulfoxides

by Yun-Han Zhang, Ya-Ting Zou, Yong-Yi Zeng, Lan Liu and Bi-Shuang Chen

Mar. Drugs 2024, 22(9), 419; https://doi.org/10.3390/md22090419 - 14 Sep 2024

Cited by 5 | Viewed by 2210

Abstract

This study explores the reasons behind the variations in the enantioselectivity of the sulfoxidation of methyl phenyl sulfide by marine-derived vanadium-dependent haloperoxidases (VHPOs). Twelve new VHPOs of marine organisms were overexpressed, purified, and tested for their ability to oxidize sulfide. Most of these marine enzymes exhibited nonenantioselective behavior, underscoring the uniqueness of AnVBPO from the brown seaweed Ascophyllum nodosum and CpVBPO from the red seaweed Corallina pilulifera, which produce (R)- and (S)-sulfoxides, respectively. The enantioselective sulfoxidation pathway is likely due to direct oxygen transfer within the VHPO active site. This was demonstrated through molecular docking and molecular dynamics simulations, which revealed differences in the positioning of sulfide within AnVBPO and CpVBPO, thus explaining their distinct enantioselectivities. Nonenantioselective VHPOs probably follow a different oxidation pathway, initiating with sulfide oxidation to form a positively charged radical. Further insights were gained from studying the catalytic effect of VO₄³⁻ on H₂O₂-driven sulfoxidation. This research improves the understanding of VHPO-mediated sulfoxidation and aids in developing biocatalysts for sulfoxide synthesis. Full article

(This article belongs to the Special Issue Advances of Marine-Derived Enzymes)

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13 pages, 2691 KB

Open AccessArticle

N-Doped Carbon/CeO₂ Composite as a Biomimetic Catalyst for Antibacterial Application

by Nan Wang, Xiaofan Zhai, Fang Guan, Ruiyong Zhang, Baorong Hou and Jizhou Duan

Int. J. Mol. Sci. 2023, 24(3), 2445; https://doi.org/10.3390/ijms24032445 - 26 Jan 2023

Cited by 19 | Viewed by 2801

Abstract

Exploring new and high efficiency mimic enzymes is a vital and novel strategy for antibacterial application. Haloperoxidase-like enzymes have attracted wide attention thanks to their amazing catalytic property for hypohalous acid generation from hydrogen peroxide and halides. However, few materials have displayed halogenating catalytic performance until now. Herein, we synthesized N-doped C/CeO₂ (N-C/CeO₂) composite materials by a combination of the liquid and solid-state method. N-C/CeO₂ can possess haloperoxidase-like catalytic activity by catalyzing the bromination of organic signaling compounds (phenol red) with H₂O₂ at a wide range of temperatures (20 °C to 55 °C), with a solution color changing from yellow to blue. Meanwhile, it exhibits high catalytic stability/recyclability in the catalytic reaction. The synthesized N-C/CeO₂ composite can effectively catalyze the oxidation of Br⁻ with H₂O₂ to produce HBrO without the presence of phenol red. The produced HBrO can resist typical marine bacteria like Pseudomonas aeruginosa. This study provides an efficient biomimetic haloperoxidase and a novel sustainable method for antibacterial application. Full article

(This article belongs to the Special Issue Development and Characterisation of Novel Polymeric Materials and Composites)

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13 pages, 5966 KB

Open AccessEditor’s ChoiceArticle

Ce-MOF with Intrinsic Haloperoxidase-Like Activity for Ratiometric Colorimetric Detection of Hydrogen Peroxide

by Yanyan Cheng, Ling Liang, Fanggui Ye and Shulin Zhao

Biosensors 2021, 11(7), 204; https://doi.org/10.3390/bios11070204 - 23 Jun 2021

Cited by 53 | Viewed by 6561

Abstract

Metal–organic framework (MOF) nanozymes, as emerging members of the nanozymes, have received more and more attention due to their composition and structural characteristics. In this work, we report that mixed-valence state Ce-MOF (MVCM) has intrinsic haloperoxidase-mimicking activity. MVCM was synthesized by partial oxidation method using Ce-MOF as a precursor. In the presence of H₂O₂ and Br⁻, MVCM can catalyze oxidative bromination of chromogenic substrate phenol red (PR) to produce the blue product bromophenol blue (Br₄PR), showing good haloperoxidase-like activity. Because of the special chromogenic substrate, we constructed a ratiometric colorimetric-sensing platform by detecting the absorbance of the MVCM-(PR, Br⁻) system at wavelengths of 590 and 430, for quantifying H₂O₂, where the detection limit of the H₂O₂ is 3.25 μM. In addition, the haloperoxidase-mimicking mechanism of the MVCM is proposed. Moreover, through enzyme kinetics monitoring, the K_m (H₂O₂ and NH₄Br) of the MVCM is lower than that of cerium oxide nanomaterials, indicating that the MVCM has a stronger binding affinity for H₂O₂ and NH₄Br than other materials. This work provides more application prospects for the development of nanozymes in the field of biosensors in the future. Full article

(This article belongs to the Special Issue Biosensors in Food Analysis and Environmental Detection)

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15 pages, 3101 KB

Open AccessArticle

Exploring the Role of Phenylalanine Residues in Modulating the Flexibility and Topography of the Active Site in the Peroxygenase Variant PaDa-I

by Joaquin Ramirez-Ramirez, Javier Martin-Diaz, Nina Pastor, Miguel Alcalde and Marcela Ayala

Int. J. Mol. Sci. 2020, 21(16), 5734; https://doi.org/10.3390/ijms21165734 - 10 Aug 2020

Cited by 12 | Viewed by 4653

Abstract

Unspecific peroxygenases (UPOs) are fungal heme-thiolate enzymes able to catalyze a wide range of oxidation reactions, such as peroxidase-like, catalase-like, haloperoxidase-like, and, most interestingly, cytochrome P450-like. One of the most outstanding properties of these enzymes is the ability to catalyze the oxidation a wide range of organic substrates (both aromatic and aliphatic) through cytochrome P450-like reactions (the so-called peroxygenase activity), which involves the insertion of an oxygen atom from hydrogen peroxide. To catalyze this reaction, the substrate must access a channel connecting the bulk solution to the heme group. The composition, shape, and flexibility of this channel surely modulate the catalytic ability of the enzymes in this family. In order to gain an understanding of the role of the residues comprising the channel, mutants derived from PaDa-I, a laboratory-evolved UPO variant from Agrocybe aegerita, were obtained. The two phenylalanine residues at the surface of the channel, which regulate the traffic towards the heme active site, were mutated by less bulky residues (alanine and leucine). The mutants were experimentally characterized, and computational studies (i.e., molecular dynamics (MD)) were performed. The results suggest that these residues are necessary to reduce the flexibility of the region and maintain the topography of the channel. Full article

(This article belongs to the Special Issue OxiZymes)

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