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Son, Sangkeun,Jang, Mina,Lee, Byeongsan,Hong, Young-Soo,Ko, Sung-Kyun,Jang, Jae-Hyuk,Ahn, Jong Seog American Chemical Society and American Society of 2018 Journal of natural products Vol.81 No.10
<P>The advances of genomic sequence analyses and genome mining tools have enabled the exploration of untapped microbial natural products. Through genome mining studies to discover cryptic natural products, we found biosynthetic genes encoding a new lasso peptide in the genome sequence of a soil bacterium, <I>Streptomyces</I> sp. KCB13F003 isolated from Ulleung Island (a small volcanic island), Korea. The production and purification of the encoded peptide, named ulleungdin, were achieved by optimizing the culture conditions followed by LC-MS-targeted isolation. Structure elucidation was performed by NMR spectroscopic and MS spectrometric analyses and chemical means (Marfey’s and GITC derivatizations), proving ulleungdin to be a new 15-mer class II lasso peptide with a threaded structure. Biological evaluation with the cell invasion assay and time-lapse cell tracking analysis revealed that ulleungdin has significant inhibitory activities against cancer cell invasion and migration.</P> [FIG OMISSION]</BR>
Production of Bioactive 3’-Hydroxystilbene Compounds Using the Flavin-Dependent Monooxygenase Sam5
( Kyung Taek Heo ),( Byeongsan Lee ),( Sangkeun Son ),( Jong Seog Ahn ),( Jae-hyuk Jang ),( Young-soo Hong ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.7
The flavin-dependent monooxygenase Sam5 was previously reported to be a bifunctional hydroxylase with coumarate 3-hydroxylase and resveratrol 3’-hydroxylase activities. In this article, we showed the Sam5 enzyme has 3’-hydroxylation activities for methylated resveratrols (pinostilbene and pterostilbene), hydroxylated resveratrol (oxyresveratrol), and glycosylated resveratrol (piceid) as substrates. However, piceid, a glycone-type stilbene used as a substrate for bioconversion experiments with the Sam5 enzyme expressed in Escherichia coli, did not convert to the hydroxylated compound astringin, but it was converted by in vitro enzyme reactions. Finally, we report a novel catalytic activity of Sam5 monooxygenase for the synthesis of piceatannol derivatives, 3’-hydroxylated stilbene compounds. Development of this bioproduction method for the hydroxylation of stilbenes is challenging because of the difficulty in expressing P450-type hydroxylase in E. coli and regiospecific chemical synthesis.
Hygrolansamycins A-D, O-Heterocyclic Macrolides from Streptomyces sp. KCB17JA11
( Jun-pil Jang ),( Byeongsan Lee ),( Kyung Taek Heo ),( Tae Hoon Oh ),( Hyeok-won Lee ),( Sung-kyun Ko ),( Bang Yeon Hwang ),( Jae-hyuk Jang ),( Young-soo Hong ) 한국미생물생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.10
Six ansamycin derivatives were isolated from the culture broth of Streptomyces sp. KCB17JA11, including four new hygrolansamycins A-D (1-4) and known congeners divergolide O (5) and hygrocin C (6). Compounds 1-5 featured an unusual six-membered O-heterocyclic moiety. The isolation workflow was guided by a Molecular Networking-based dereplication strategy. The structures of 1-4 were elucidated using NMR and HRESIMS experiments, and the absolute configuration was established by the Mosher’s method. Compound 2 exhibited mild cytotoxicity against five cancer cell lines with IC<sub>50</sub> values ranging from 24.60 ± 3.37 μM to 49.93 ± 4.52 μM.
( Hemraj Rimal ),( Sang-cheol Yu ),( Byeongsan Lee ),( Young-soo Hong ),( Tae-jin Oh ) 한국미생물 · 생명공학회 2019 Journal of microbiology and biotechnology Vol.29 No.1
Geldanamycin and its derivatives, inhibitors of heat shock protein 90, are considered potent anticancer drugs, although their biosynthetic pathways have not yet been fully elucidated. The key step of conversion of 4,5-dihydrogeldanamycin to geldanamycin was expected to catalyze by a P450 monooxygenase, Gel16. The adequate bioconversions by cytochrome P450 mostly rely upon its interaction with redox partners. Several ferredoxin and ferredoxin reductases are available in the genome of certain organisms, but only a few suitable partners can operate in full efficiency. In this study, we have expressed cytochrome P450 gel16 in Escherichia coli and performed an in vitro assay using 4,5-dihydrogeldanamycin as a substrate. We demonstrated that the in silico method can be applicable for the efficient mining of convenient endogenous redox partners (9 ferredoxins and 6 ferredoxin reductases) against CYP Gel16 from Streptomyces hygroscopicus. The distances for ligand FDX4-FDR6 were found to be 9.384 A. Similarly, the binding energy between Gel16-FDX4 and FDX4-FDR6 were -611.88 kcal/mol and -834.48 kcal/mol, respectively, suggesting the lowest distance and binding energy rather than other redox partners. These findings suggest that the best redox partners of Gel16 could be NADPH → FDR6 → FDX4 → Gel16.
Hwang Gwi Ja,Roh Jongtae,Son Sangkeun,Lee Byeongsan,Jang Jun-Pil,Hur Jae-Seoun,Hong Young-Soo,Ahn Jong Seog,Ko Sung-Kyun,Jang Jae-Hyuk 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.11
A recently bioinformatic analysis of genomic sequences of fungi indicated that fungi are able to produce more secondary metabolites than expected. Despite their potency, many biosynthetic pathways are silent in the absence of specific culture conditions or chemical cues. To access cryptic metabolism, 108 fungal strains isolated from various sites were cultured with or without Streptomyces sp. 13F051 which mainly produces trichostatin analogues, followed by comparison of metabolic profiles using LC-MS. Among the 108 fungal strains, 14 produced secondary metabolites that were not recognized or were scarcely produced in mono-cultivation. Of these two fungal strains, Myrmecridium schulzeri 15F098 and Scleroconidioma sphagnicola 15S058 produced four new compounds (1-4) along with a known compound (5), demonstrating that all four compounds were produced by physical interaction with Streptomyces sp. 13F051. Bioactivity evaluation indicated that compounds 3-5 impede migration of MDA-MB-231 breast cancer cells.
Son, Sangkeun,Hong, Young-Soo,Jang, Mina,Heo, Kyung Taek,Lee, Byeongsan,Jang, Jun-Pil,Kim, Jong-Won,Ryoo, In-Ja,Kim, Won-Gon,Ko, Sung-Kyun,Kim, Bo Yeon,Jang, Jae-Hyuk,Ahn, Jong Seog American Chemical Society and American Society of 2017 Journal of natural products Vol.80 No.11
<P>Analysis of the genome sequence of <I>Streptomyces</I> sp. KCB13F003 showed the presence of a cryptic gene cluster encoding flavin-dependent halogenase and nonribosomal peptide synthetase. Pleiotropic approaches using multiple culture media followed by LC-MS-guided isolation and spectroscopic analysis enabled the identification of two new chlorinated cyclic hexapeptides, ulleungmycins A and B (<B>1</B> and <B>2</B>). Their structures, including absolute configurations, were determined by 1D and 2D NMR techniques, advanced Marfey’s analysis, and GITC derivatization. The new peptides, featuring unusual amino acids 5-chloro-<SMALL>l</SMALL>-tryptophan and <SMALL>d</SMALL>-homoleucine, exhibited moderate antibacterial activities against Gram-positive pathogenic bacteria including methicillin-resistant and quinolone-resistant <I>Staphylococcus aureus</I>.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jnprdf/2017/jnprdf.2017.80.issue-11/acs.jnatprod.7b00660/production/images/medium/np-2017-00660j_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/np7b00660'>ACS Electronic Supporting Info</A></P>
Son, Sangkeun,Ko, Sung-Kyun,Kim, Seung Min,Kim, Eun,Kim, Gil Soo,Lee, Byeongsan,Ryoo, In-Ja,Kim, Won-Gon,Lee, Jung-Sook,Hong, Young-Soo,Jang, Jae-Hyuk,Ahn, Jong Seog American Chemical Society and American Society of 2018 Journal of natural products Vol.81 No.11
<P>Three cyclic lipopeptides, including one known (<B>1</B>) and two new (<B>2</B> and <B>3</B>) compounds, that possess the rare enamide linkage group were discovered from <I>Streptomyces</I> sp. KCB14A132, an actinobacterium isolated from a soil sample collected from Jeung Island, Korea. The NMR and MS-based characterization showed that they differed in the amino acid residues in the peptide backbone. Application of Marfey’s analysis, GITC derivatization, and modified Mosher’s method, as well as ECD measurements provided the absolute configurations of enamidonin (<B>1</B>) and those of new compounds enamidonins B and C (<B>2</B> and <B>3</B>). The two new enamidonin analogues were shown to exhibit antibacterial activity against Gram-positive bacteria including methicillin-resistant and quinolone-resistant <I>Staphylococcus aureus</I>. Furthermore, evaluation of the extraction conditions and a close inspection of the LC-MS chromatograms revealed that the <I>N</I>,<I>N</I>-acetonide unit of the enamidonin family was formed during the acetone extraction process. The chemically prepared deacetonide derivatives of enamidonins were found to lack antibacterial activity, demonstrating that the dimethylimidazolidinone residue is necessary for antibacterial activity.</P> [FIG OMISSION]</BR>