Journal of Microbiology

Jong-Tae Park

2 Articles

Identification and Characterization of HEPN‑MNT Type II TA System from Methanothermobacter thermautotrophicus ΔH: Wonho Choi , Anoth Maharjan , Hae Gang Im , Ji-Young Park , Jong-Tae Park , Jung-Ho Park; J. Microbiol. 2023;61(4):411-421. Published online April 18, 2023; DOI: https://doi.org/10.1007/s12275-023-00041-9

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Toxin-antitoxin (TA) systems are widespread in bacteria and archaea plasmids and genomes to regulate DNA replication, gene transcr!ption, or protein translation. Higher eukaryotic and prokaryotic nucleotide-binding (HEPN) and minimal nucleotidyltransferase (MNT) domains are prevalent in prokaryotic genomes and constitute TA pairs. However, three gene pairs (MTH304/305, 408/409, and 463/464) of Methanothermobacter thermautotropicus ΔH HEPN-MNT family have not been studied as TA systems. Among these candidates, our study characterizes the MTH463/MTH464 TA system. MTH463 expression inhibited Escherichia coli growth, whereas MTH464 did not and blocked MTH463 instead. Using site-directed MTH463 mutagenesis, we determined that amino acids R99G, H104A, and Y106A from the R[ɸX]4-6H motif are involved with MTH463 cell toxicity. Furthermore, we established that purified MTH463 could degrade MS2 phage RNA, whereas purified MTH464 neutralized MTH463 activity in vitro. Our results indicate that the endonuclease toxin MTH463 (encoding a HEPN domain) and its cognate antitoxin MTH464 (encoding the MNT domain) may act as a type II TA system in M. thermautotropicus ΔH. This study provides initial and essential information studying TA system functions, primarily archaea HEPN-MNT family.

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Extensive Genomic Rearrangement of Catalase-Less Cyanobloom-Forming Microcystis aeruginosa in Freshwater Ecosystems
Minkyung Kim, Jaejoon Jung, Wonjae Kim, Yerim Park, Che Ok Jeon, Woojun Park
Journal of Microbiology.2024; 62(11): 933. CrossRef

Characterization of a cold-adapted debranching enzyme and its role in glycogen metabolism and virulence of Vibrio vulnificus MO6-24/O: Ah-Reum Han , Haeyoung Kim , Jong-Tae Park , Jung-Wan Kim; J. Microbiol. 2022;60(4):375-386. Published online February 14, 2022; DOI: https://doi.org/10.1007/s12275-022-1507-3

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Abstract PDF

Vibrio vulnificus MO6-24/O has three genes annotated as debranching enzymes or pullulanase genes. Among them, the gene encoded by VVMO6_03032 (vvde1) shares a higher similarity at the amino acid sequence level to the glycogen debranching enzymes, AmyX of Bacillus subtilis (40.5%) and GlgX of Escherichia coli (55.5%), than those encoded by the other two genes. The vvde1 gene encoded a protein with a molecular mass of 75.56 kDa and purified Vvde1 efficiently hydrolyzed glycogen and pullulan to shorter chains of maltodextrin and maltotriose (G3), respectively. However, it hydrolyzed amylopectin and soluble starch far less efficiently, and β-cyclodextrin (β-CD) only rarely. The optimal pH and temperature of Vvde1 was 6.5 and 25°C, respectively. Vvde1 was a cold-adapted debranching enzyme with more than 60% residual activity at 5°C. It could maintain stability for 2 days at 25°C and 1 day at 35°C, but it destabilized drastically at 40°C. The Vvde1 activity was inhibited considerably by Cu2+, Hg2+, and Zn2+, while it was slightly enhanced by Co2+, Ca2+, Ni2+, and Fe2+. The vvde1 knock-out mutant accumulated more glycogen than the wild-type in media supplemented with 1.0% maltodextrin; however, the side chain length distribution of glycogen was similar to that of the wild-type except G3, which was much more abundant in the mutant. Therefore, Vvde1 seemed to debranch glycogen with the degree of polymerization 3 (DP3) as the specific target branch length. Virulence of the pathogen against Caenorhabditis elegans was attenuated significantly by the vvde1 mutation. These results suggest that Vvde1 might be a unique glycogen debranching enzyme that is involved in both glycogen utilization and shaping of glycogen molecules, and contributes toward virulence of the pathogen.

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Characterization of glycogen-related glycoside hydrolase glgX and glgB from Klebsiella pneumoniae and their roles in biofilm formation and virulence
Xinyue Liu, Jialin Li, Ruibing Wu, Liping Bai
Frontiers in Cellular and Infection Microbiology.2024;[Epub] CrossRef
Function of the mdxR gene encoding a novel regulator for carbohydrate metabolism and sporulation in Bacillus subtilis 168
Tianshi Wang, Jung-Wan Kim
Archives of Microbiology.2023;[Epub] CrossRef
Identification of a novel cyclomaltodextrinase annotated as a neopullulanase in the genome of Bacillus cereus
Bo-Ram Park, Davoodbasha MubarakAli, Jung-Wan Kim
Archives of Microbiology.2023;[Epub] CrossRef
Functional conservation of specialized ribosomes bearing genome-encoded variant rRNAs in Vibrio species
Younkyung Choi, Eunkyoung Shin, Minho Lee, Ji-Hyun Yeom, Kangseok Lee, Bashir Sajo Mienda
PLOS ONE.2023; 18(12): e0289072. CrossRef
Functional characterization of maltodextrin glucosidase for maltodextrin and glycogen metabolism in Vibrio vulnificus MO6-24/O
Hye-Young Kim, MubarakAli Davoodbasha, Jung-Wan Kim
Archives of Microbiology.2022;[Epub] CrossRef

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