RESUMO
Here we report the detailed measurement of long-range heteronuclear spin-spin coupling constants, especially 2, 3JCH spin-spin couplings for eight different cyclopentane derivatives. These 2, 3JCH constants were shown to be a useful tool in the determination of the relative stereochemistry in these rings. The coupling constant measurements reported here are based on two different experiments: a 2D heteronuclear correlation experiment named G-BIRDR, X-CPMG-HSQMBC and the 2D-coupled gHSQC {1H-13C} experiment
Assuntos
Ciclopentanos/química , Espectroscopia de Ressonância Magnética , Espectroscopia de Ressonância Magnética/normas , Estrutura Molecular , Padrões de ReferênciaRESUMO
Detailed measurements of long-range heteronuclear spin-spin coupling constants, especially (2, 3)J(CH) spin-spin couplings for various cyclopentane derivatives, are reported. The measurements are based on a 2D heteronuclear correlation experiment named G-BIRD(R, X)-CPMG-HSQMBC.
Assuntos
Ciclopentanos/química , Espectroscopia de Ressonância Magnética , Ciclopentanos/classificação , Ciclopentanos/normas , Estrutura Molecular , Padrões de ReferênciaRESUMO
A screening program for bioactive compounds from marine cyanobacteria led to the isolation of jamaicamides A-C. Jamaicamide A is a novel and highly functionalized lipopeptide containing an alkynyl bromide, vinyl chloride, beta-methoxy eneone system, and pyrrolinone ring. The jamaicamides show sodium channelblocking activity and fish toxicity. Precursor feeding to jamaicamide-producing cultures mapped out the series of acetate and amino acid residues and helped develop an effective cloning strategy for the biosynthetic gene cluster. The 58 kbp gene cluster is composed of 17 open reading frames that show an exact colinearity with their expected utilization. A novel cassette of genes appears to form a pendent carbon atom possessing the vinyl chloride functionality; at its core this contains an HMG-CoA synthase-like motif, giving insight into the mechanism by which this functional group is created.
Assuntos
Amidas/química , Cianobactérias/química , Toxinas Marinhas/química , Neurotoxinas/química , Peptídeos/química , Pirrolidinonas/química , Amidas/isolamento & purificação , Amidas/farmacologia , Animais , Sequência de Bases , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cianobactérias/genética , Cianobactérias/metabolismo , Humanos , Lipopeptídeos , Lipoproteínas/química , Lipoproteínas/isolamento & purificação , Lipoproteínas/farmacologia , Toxinas Marinhas/isolamento & purificação , Toxinas Marinhas/farmacologia , Camundongos , Dados de Sequência Molecular , Estrutura Molecular , Família Multigênica , Neurotoxinas/isolamento & purificação , Neurotoxinas/farmacologia , Peptídeos/isolamento & purificação , Peptídeos/farmacologia , Estrutura Terciária de Proteína , Pirrolidinonas/isolamento & purificação , Pirrolidinonas/farmacologia , Canais de Sódio/efeitos dos fármacos , Canais de Sódio/fisiologiaRESUMO
Hectochlorin (1) was isolated from marine isolates of Lyngbya majuscula collected from Hector Bay, Jamaica, and Boca del Drago Beach, Bocas del Toro, Panama. The planar structure was deduced by one- and two-dimensional NMR spectroscopy. X-ray crystallography was used to determine the absolute stereochemistry of hectochlorin as 2S,3S,14S,22S. Hectochlorin is equipotent to jasplakinolide (5) in its ability to promote actin polymerization, but unlike jasplakinolide, is unable to displace a fluorescent phalloidin analogue from polymerized actin. In addition, hectochlorin shows both a unique profile of cytotoxicity by the COMPARE algorithm and potent inhibitory activity toward the fungus Candida albicans. Structurally, hectochlorin resembles dolabellin and the recently reported lyngbyabellin class of compounds.