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WS9326H, an Antiangiogenic Pyrazolone-Bearing Peptide from an Intertidal Mudflat Actinomycete
Bae, Munhyung,Oh, Jedo,Bae, Eun Seo,Oh, Joonseok,Hur, Joonseong,Suh, Young-Ger,Lee, Sang Kook,Shin, Jongheon,Oh, Dong-Chan American Chemical Society 2018 ORGANIC LETTERS Vol.20 No.7
<P>WS9326H (<B>1</B>), a new cyclic peptide, was isolated from a mudflat-derived <I>Streptomyces</I> strain. Based on analysis by 1D/2D NMR, UV spectroscopy, and mass spectrometry, compound <B>1</B> was determined to have the gross structure of a cyclic heptapeptide bearing an unprecedented pyrazolone ring connected to a <SMALL>D</SMALL>-arabinitol via an amide bond. The absolute configuration of <B>1</B> was established by multistep chemical derivatizations, comprehensive NMR, and LC/MS analyses of the derivatives and quantum mechanics-based computational methods. WS9326H (<B>1</B>) displayed significant antiangiogenesis activity.</P> [FIG OMISSION]</BR>
Bae, Munhyung,An, Joon Soo,Bae, Eun Seo,Oh, Jedo,Park, So Hyun,Lim, Yeonjung,Ban, Yeon Hee,Kwon, Yun,Cho, Jang-Cheon,Yoon, Yeo Joon,Lee, Sang Kook,Shin, Jongheon,Oh, Dong-Chan American Chemical Society 2019 Organic letters Vol.21 No.10
<P>The chemical analysis of a <I>Streptomyces</I> strain, from a Korean volcanic island, discovered new benz[<I>a</I>]anthracene dimers linked by a thioether bond. The structures of donghaesulfins A and B (<B>1</B> and <B>2</B>) were elucidated by spectroscopic analysis including energy-dispersive X-ray. Their configurations were determined by ROESY NMR data, DP4 calculations, the modified Mosher’s method, and ECD calculations. Donghaesulfins A (<B>1</B>) induced quinone reductase, whereas donghaesulfin B (<B>2</B>) displayed antiangiogenesis activity.</P> [FIG OMISSION]</BR>
Bae, Munhyung,Kim, Heegyu,Moon, Kyuho,Nam, Sang-Jip,Shin, Jongheon,Oh, Ki-Bong,Oh, Dong-Chan American Chemical Society 2015 ORGANIC LETTERS Vol.17 No.3
<P>Mohangamides A and B (<B>1</B>–<B>2</B>) were discovered from a marine <I>Streptomyces</I> sp. collected in an intertidal mud flat. The structures of the compounds were elucidated as novel dilactone-tethered pseudodimeric peptides bearing two unusual acyl chains and 14 amino acid residues based on comprehensive spectroscopic analysis. The absolute configurations of the mohangamides were determined by chemical derivatizations, followed by chromatographic and spectroscopic analyses. Mohangamide A displayed strong inhibitory activity against <I>Candida albicans</I> isocitrate lyase.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/orlef7/2015/orlef7.2015.17.issue-3/ol5037248/production/images/medium/ol-2014-037248_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ol5037248'>ACS Electronic Supporting Info</A></P>
Structural Revision of Baulamycin A and Structure–Activity Relationships of Baulamycin A Derivatives
Sengupta, Sandip,Bae, Munhyung,Oh, Dong-Chan,Dash, Uttam,Kim, Hak Joong,Song, Woon Young,Shin, Injae,Sim, Taebo American Chemical Society 2017 Journal of organic chemistry Vol.82 No.24
<P>Total synthesis of the proposed structure of baulamycin A was performed. The spectral properties of the synthetic compound differ from those reported for the natural product. On the basis of comprehensive NMR study, we proposed two other possible structures for natural baulamycin A. Total syntheses of these two substances were performed, which enabled assignment of the correct structure of baulamycin A. Key features of the convergent and fully stereocontrolled route include Evans Aldol and Brown allylation reactions to construct the left fragment, a prolinol amide-derived alkylation/desymmetrization to install the methyl-substituted centers in the right fragment, and finally, a Carreira alkynylation to join both fragments. In addition, we have determined the inhibitory activities of novel baulamycin A derivatives against the enzyme SbnE. This SAR study provides useful insight into the design of novel SbnE inhibitors that overcome the drug resistance of pathogens, which cause life-threatening infections.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/joceah/2017/joceah.2017.82.issue-24/acs.joc.7b01719/production/images/medium/jo-2017-017198_0020.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jo7b01719'>ACS Electronic Supporting Info</A></P>
Anti-Neurodegenerative Biflavonoid Glycosides from <i>Impatiens balsamina</i>
Kim, Chung Sub,Bae, Munhyung,Oh, Joonseok,Subedi, Lalita,Suh, Won Se,Choi, Sang Zin,Son, Mi Won,Kim, Sun Yeou,Choi, Sang Un,Oh, Dong-Chan,Lee, Kang Ro American Society of Pharmacognosy 2017 Journal of natural products Vol.80 No.2
<P>Four biflavonoid glycosides, balsamisides A-D (1-4), and nine known compounds (5-13) were obtained from the white petals of Impatiens balsamina. The 2D structures of the purified phytochemicals were established using conventional NMR techniques in addition to the new long-range HSQMBC NMR experiment. Acid hydrolysis followed by experimental and quantum-mechanics-based ECD data analysis permitted full configurational assignment of the purified metabolites. Compounds 1-13 were assessed for their potential to impede the generation of nitric oxide in lipopolysaccharide-stimulated BV2 cells. They were also investigated for potential neuroprotective activity using C6 cells and cytotoxicity against some human tumor cell lines, but were inactive (IC50 > 10 mu M) against all the cell lines.</P>
Unprecedented Noncanonical Features in the WS9326A Nonribosomal Peptide Synthetase Assembly Line
Jung Min KIM,Myoun-Su KIM,Munhyung BAE,Ye-Eun JUNG,Jeong Sang YI,Sunghoon HWANG,Myoung Chong SONG,Yeon Hee BAN,Eun Seo BAE,Suckchang HONG,Sang Kook LEE,Sun-Shin CHA,Dong-Chan OH,Yeo Joon YOON 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
A growing number of nonribosomal peptide synthetase (NRPS) assembly lines violating the “co-linearity rule,” where the number and order of NRPS modules indicate to the number and sequence of amino acids in the corresponding product, have been discovered. To understand biosynthetic mechanism of such NRP, NRPS of Streptomyces sp. SNM55 was investigated. Systematic inactivation of NRPS domains and translocation of the thioesterase (TE) domains unveiled several unprecedented nonlinear NRPS assembly processes during the biosynthesis of the cyclodepsipeptide WS9326A in S. sp. SNM55. The WS9326 NRPS assembly line involves two type II TE (TEII)-like enzymes responsible for the transfer of activated amino acids from two stand-alone adenylation (A)-thiolation (T) didomain modules with different specificities to the ‘A-less’ condensation (C)-T module, which operates iteratively, catalyzing two chain elongation steps. This biosynthetic pathway includes the first example of NRPS module skipping, where the interpolated C and T domains are required for chain transfer. Understanding such untapped nonlinear biosynthetic strategies will provide potentially valuable tools for engineered biosynthesis of these complex natural products.
Shin, Yern-Hyerk,Beom, Ji Yoon,Chung, Beomkoo,Shin, Yoonho,Byun, Woong Sub,Moon, Kyuho,Bae, Munhyung,Lee, Sang Kook,Oh, Ki-Bong,Shin, Jongheon,Yoon, Yeo Joon,Oh, Dong-Chan American Chemical Society 2019 ORGANIC LETTERS Vol.21 No.6
<P>Bombyxamycins A and B (<B>1</B> and <B>2</B>) were discovered from a silkworm gut <I>Streptomyces</I> bacterium. Spectroscopic analysis and multiple-step chemical derivatization identified them as 26-membered cyclic lactams with polyene features. Bombyxamycin A showed significant antibacterial and antiproliferative effects. The bombyxamycin biosynthetic gene cluster was identified by genetic analysis. Gene deletion experiments confirmed that the cytochrome P450 BomK is responsible for the generation of <B>2</B>, which unprecedentedly bears tetrahydrofuran in its macrocyclic ring.</P> [FIG OMISSION]</BR>