Generation and Application of All Possible Conformations of Cyclic Tryptophan within and beyond Post-translational Modification.

Isoprenylation of the indole C3-position of tryptophan accompanied by cyclization (c-Trp) is one of the most attractive post-translational modifications because of C-C bond formation and drastic conformational alteration. As the modification generates two stereoisomers of the 6/5/5-fused ring system and consequently, a mixture of four possible conformations as considered in proline, it is expected to influence the biological activity in quorum sensing pheromone ComX containing the c-Trp residue. In this study, the simultaneous control of the amide equilibrium and pyrrolidine ring puckering was achieved by utilizing an N-carbamoylated and α-methylated 6/5/5-fused ring system.

Differentiation-Promoting Effects of Okeaniamides A and B from an sp. Marine Cyanobacterium on Preadipocytes.

The linear lipopeptides okeaniamide A () and okeaniamide B () were isolated from an sp. marine cyanobacterium collected in Okinawa. The structures of these compounds were established by spectroscopic analyses, and the absolute configurations were elucidated based on a combination of chemical degradations, Marfey's analysis, and derivatization reactions.

Unique Initiation and Termination Mechanisms Involved in the Biosynthesis of a Hybrid Polyketide-Nonribosomal Peptide Lyngbyapeptin B Produced by the Marine Cyanobacterium .

Lyngbyapeptin B is a hybrid polyketide-nonribosomal peptide isolated from particular marine cyanobacteria. In this report, we carried out genome sequence analysis of a producer cyanobacterium to understand the biosynthetic mechanisms that generate the unique structural features of lyngbyapeptin B, including the ()-3-methoxy-2-butenoyl starter unit and the C-terminal thiazole moiety. We identified a putative lyngbyapeptin B biosynthetic () gene cluster comprising nine open reading frames that include two polyketide synthases (PKSs: LynB1 and LynB2), four nonribosomal peptide synthetases (NRPSs: LynB3, LynB4, LynB5, and LynB6), a putative nonheme diiron oxygenase (LynB7), a type II thioesterase (LynB8), and a hypothetical protein (LynB9).

Isolation of Caldorazole, a Thiazole-Containing Polyketide with Selective Cytotoxicity under Glucose-Restricted Conditions.

Caldorazole () was isolated from the marine cyanobacterium sp. collected on Ishigaki Island, Okinawa, Japan. Its structure was determined to be a new polyketide that contained two thiazole rings and an -methylenolpyruvamide moiety.

Characterization of Macroscopic Colony-Forming Filamentous Cyanobacteria from Okinawan Coasts as Potential Sources of Bioactive Compounds.

Marine macroscopic colony-forming filamentous (MMCFF) cyanobacteria are considered as prolific producers of bioactive compounds. Thus, knowledge of the diversity of MMCFF cyanobacteria as related to bioactive compound production has become very important. However, basic taxonomic studies of MMCFF cyanobacteria are lacking.

Irijimasides A-E, Macrolide Glycosides from an sp. Marine Cyanobacterium.

Irijimasides A-E (-), a series of new 14-membered macrolide glycosides, were isolated from a marine cyanobacterium collected in Okinawa. The gross structures of - were established by spectroscopic analysis, including 2D NMR, while absolute stereostructures were determined based on NOESY spectra, chemical derivatization, and ECD data. All five macrolides suppressed receptor activator of nuclear factor-κB ligand (RANKL)-induced tartrate-resistant acid phosphatase (TRAP) activity in mouse RAW264 macrophage cells, indicating that these compounds inhibit osteoclast formation.

Ikoamide, an Antimalarial Lipopeptide from an sp. Marine Cyanobacterium.

An antimalarial lipopeptide, ikoamide, was isolated from an sp. marine cyanobacterium. Its gross structure was established by spectroscopic analyses, and the absolute configuration was clarified based on a combination of chiral-phase HPLC analyses, spectroscopic analyses, and derivatization reactions.

Minnamide A, a Linear Lipopeptide from the Marine Cyanobacterium Okeania hirsuta.

Minnamide A is a lipopeptide with a unique repeating structure consisting of hydroxy and proposed β-branched methyl groups. The absolute configuration of minnamide A was determined by a combination of chemical degradation, chiral HPLC analyses, and synthetic methods. Minnamide A showed growth-inhibitory activity toward HeLa cells with an IC value of 0.

Isolation of Jahanene and Jahanane, and Total Synthesis of the Jahanyne Family.

Two new jahanyne analogues, jahanene and jahanane, highly N-methylated lipopeptides, were isolated from a marine cyanobacterium Okeania sp., and their structures were determined by NMR and MS. In addition, we achieved total syntheses of the jahanyne family and assessed their activities.

Izenamides A and B, Statine-Containing Depsipeptides, and an Analogue from a Marine Cyanobacterium.

Izenamides A, B, and C (1-3), new linear depsipeptides, were isolated from a taxonomically distinct marine cyanobacterium. Izenamides A and B contain a statine moiety [(3 S,4 S)-4-amino-3-hydroxy-6-methylheptanoic acid] and inhibited the activity of cathepsin D, an aspartic peptidase. Meanwhile, izenamides did not show growth-inhibitory activity against HeLa, HL60, or MCF-7 cells at up to 10 μM.

Ypaoamides B and C, Linear Lipopeptides from an Okeania sp. Marine Cyanobacterium.

Two new pyrrolinone-containing lipopeptides, ypaoamides B (1) and C (2), were isolated from an Okeania sp. marine cyanobacterium collected in Okinawa. Their structures were determined by spectroscopic analysis and Marfey's analysis of acid hydrolysates.

Three New Malyngamides from the Marine Cyanobacterium Moorea producens.

Three new compounds of the malyngamide series, 6,8-di--acetylmalyngamide 2 (), 6--acetylmalyngamide 2 (), and -demethyl-isomalyngamide I (), were isolated from the marine cyanobacterium . Their structures were determined by spectroscopic analysis and chemical derivatization and degradation. These compounds stimulated glucose uptake in cultured L6 myotubes.

Kohamamides A, B, and C, Cyclic Depsipeptides from an Okeania sp. Marine Cyanobacterium.

Kohamamides A, B, and C (1-3), new cyclic depsipeptides that belong to the kulolide superfamily, were isolated from an Okeania sp. marine cyanobacterium. Their structures were elucidated by spectroscopic analyses and degradation reactions.

Biseokeaniamides A, B, and C, Sterol O-Acyltransferase Inhibitors from an Okeania sp. Marine Cyanobacterium.

Biseokeaniamides A, B, and C (1-3), structurally novel sterol O-acyltransferase (SOAT) inhibitors, were isolated from an Okeania sp. marine cyanobacterium. Their structures were elucidated by spectroscopic analyses and degradation reactions.

Isolation and Total Synthesis of Hoshinolactam, an Antitrypanosomal Lactam from a Marine Cyanobacterium.

In the search for new antiprotozoal substances, hoshinolactam, an antitrypanosomal lactam, was isolated from a marine cyanobacterium. The gross structure was elucidated by spectroscopic analyses, and the absolute configuration was determined by the first total synthesis. Hoshinolactam showed potent antitrypanosomal activity with an IC value of 3.

Kanamienamide, an Enamide with an Enol Ether from the Marine Cyanobacterium Moorea bouillonii.

Kanamienamide, an enamide with an enol ether, was isolated from the marine cyanobacterium Moorea bouillonii. The gross structure was established by spectroscopic analyses, and the relative stereochemistry was elucidated on the basis of the analyses of NOESY correlations and H-H coupling constants. The absolute configuration was determined on the basis of the chiral HPLC analysis of the N-Me-Leu derived from kanamienamide.