Understanding How Bacterial Enzymes Break Down Garlic Compounds

Greg Howard
30th May, 2024

Understanding How Bacterial Enzymes Break Down Garlic Compounds

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Shandong University found bacterial enzymes that can produce thiosulfinates, compounds with strong antimicrobial properties, from garlic
  • These bacterial enzymes showed high activity in converting garlic compounds into thiosulfinates, potentially overcoming the limited availability of the natural enzyme alliinase
  • The study suggests that using these bacterial enzymes could enhance the production of thiosulfinates, offering new ways to protect crops from pests and pathogens
Thiosulfinates, such as allicin, are sulfur-containing compounds known for their significant antimicrobial properties. These compounds are derived from garlic (Allium sativum) and have been shown to possess broad-spectrum biological activities, including antifungal, antibacterial, and even nematode control capabilities[2]. However, the limited availability of the enzyme alliinase, essential for the biosynthesis of thiosulfinates, has restricted their wider application in agriculture and food industries. A recent study by researchers at Shandong University aimed to address this bottleneck by exploring bacterial sources of alliinase and characterizing their catalytic properties[1]. The study identified two bacterial cystathionine β-lyases (MetCs) from Allium sativum rhizosphere isolates that demonstrated high alliinase activity toward L-(-)-alliin, a precursor of allicin. Further metagenomic analysis revealed that a cystathionine β-lyase from Bacillus cereus (BcPatB) exhibited even higher activity toward both L-(±)-alliin and L-(+)-alliin, with activities of 208.6 and 225.1 U mg^-1, respectively. The identification of these bacterial enzymes is significant because they exhibit a high preference for l-cysteine S-conjugate sulfoxides, similar to traditional Allium alliinases. This similarity extends to their phylogenetic relationship and several structural features, particularly a specific motif in the BcPatB enzyme that plays a crucial role in substrate stereospecificity. The study found that mutations at specific sites within this motif could enhance the enzyme’s activity and selectivity toward different alliin stereoisomers. These findings are particularly relevant in light of previous research demonstrating the antimicrobial properties of thiosulfinates. For instance, allicin itself has been shown to inhibit the proliferation of bacteria and fungi, including antibiotic-resistant strains like MRSA, and induce cell death in mammalian cancer cells[2]. Additionally, synthetic derivatives containing disulfide bonds have been effective against various pathogens, such as the antifungal activity of compound S8 against Monilinia fructicola and the antibacterial activity of compound S5 against Xanthomonas oryzae[3]. The ability to biosynthesize thiosulfinates more efficiently using bacterial alliinases could therefore significantly enhance their application in controlling agricultural pests and pathogens. Moreover, the study’s findings have implications for the control of root-knot nematodes (RKNs), which are a major agricultural pest affecting a wide range of crops[4]. Traditional chemical treatments for RKNs are becoming increasingly restricted due to environmental concerns, highlighting the need for alternative, environmentally benign methods. Thiosulfinates, with their demonstrated antinematode activities, could provide a valuable tool in integrated pest management strategies. The research conducted by Shandong University thus represents a significant advancement in the field of agricultural biotechnology. By leveraging bacterial alliinases with high catalytic activity, the study opens up new possibilities for the efficient production of thiosulfinates. This could lead to enhanced protection of crops and food products from microbial and nematode threats, addressing a critical need in sustainable agriculture.



Main Study

1) Identification and Characterization of Bacterial Alliinase: Resource and Substrate Stereospecificity.

Published 29th May, 2024


Related Studies

2) Allicin: chemistry and biological properties.


3) Allicin-Inspired Heterocyclic Disulfides as Novel Antimicrobial Agents.


4) Recent Advances in the Development of Environmentally Benign Treatments to Control Root-Knot Nematodes.


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