- Unique polyhalogenated peptides from the marine sponge Ircinia sp.
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Two new bromopyrrole peptides, haloirciniamide A (1) and seribunamide A (2), have been isolated from an Indonesian marine sponge of the genus Ircinia collected in the Thousand Islands (Indonesia). The planar structure of both compounds was assigned on the basis of extensive 1D and 2D NMR spectroscopy and mass spectrometry. The absolute configuration of the amino acid residues in 1 and 2 was determined by the application of Marfey's method. Compound 1 is the first dibromopyrrole cyclopeptide having a chlorohistidine ring, while compound 2 is a rare peptide possessing a tribromopyrrole ring. Both compounds failed to show significant cytotoxicity against four human tumor cell lines, and neither compound was able to inhibit the enzyme topoisomerase I or impair the interaction between programmed cell death protein PD1 and its ligand, PDL1.
- Fernández, Rogelio,Bayu, Asep,Hadi, Tri Aryono,Bueno, Santiago,Pérez, Marta,Cuevas, Carmen,Putra, Masteria Yunovilsa
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- Colony-wise Analysis of a Theonella swinhoei Marine Sponge with a Yellow Interior Permitted the Isolation of Theonellamide i
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There are several examples of marine organisms whose metabolic profiles differ among conspecifics inhabiting the same region. We have analyzed the metabolic profile of each colony of a Theonella swinhoei marine sponge with a yellow interior and noticed the patchy distribution of one metabolite. This compound was isolated and its structure was studied by a combination of spectrometric analyses and chemical degradation, showing it to be a congener in the theonellamide class of bicyclic peptides. Theonellamides had previously been isolated by us only from T. swinhoei with a white interior and not from those with a yellow interior.
- Fukuhara, Kazuya,Takada, Kentaro,Watanabe, Ryuichi,Suzuki, Toshiyuki,Okada, Shigeru,Matsunaga, Shigeki
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p. 2595 - 2599
(2018/12/13)
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- Total synthesis of nominal (11S)- and (11R)-cyclocinamide A
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The cyclocinamides possess a unique β2αβ 2α 14-membered tetrapeptide core. The initially reported biological data and intriguing structure, which was without full stereochemical identification, necessitated synthesis of both nominal (all-S) cyclocinamide A and the 11R isomer. The completed synthesis is highlighted by the use of a (cyclo)asparagine-containing dipeptide as a turn inducing fragment. Due to inconsistencies in analytical data between natural and synthetic samples, a re-evaluation of the natural product stereochemistry appears necessary.
- Garcia, Jessica M.,Curzon, Stephanie S.,Watts, Katharine R.,Konopelski, Joseph P.
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supporting information; experimental part
p. 2054 - 2057
(2012/06/29)
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