Macrocyclic Structure
Mostrando 1-12 de 17 artigos, teses e dissertações.
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1. Macrolactamas bioativas e síntese de macrociclos por reação de carbociclização radicalar mediada por hidreto de tri-n-butilestanho
This review presents natural, semi-synthetic and synthetic bioactive macrolactams and their structure-activity relationships when available. For macrolactams in clinical use the advantages and disadvantages in relation to other drugs are presented, and for synthetic macrolactams the method used in the cyclization is showed. Regarding macrocyclic synthesis by
Química Nova. Publicado em: 2008
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2. Síntese da estrutura macrocíclica dos furanoeliangolidos / Synthesis of the macrocyclic structure of Furanoheliangolides
Furanoeliangolidos são produtos naturais bioativos com peculiar estrutura macrocíclica. A síntese orgânica destes compostos tem despertado grande interesse por parte de vários pesquisadores. Particularmente, há alguns anos, o nosso grupo de pesquisa vem se dedicando, entre outras atividades, ao estudo de métodos sintéticos para a preparação do esqu
Publicado em: 2007
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3. Alcaloides pirrolizidinicos utilizados por insetos na defesa quimica contra predadores vertebrados e invertebrados
Pyrrolizidine Alkaloids (PAs) are secondary plant compounds with a unique role in the interaction between plants, herbivorous insects, and their natural enemies relationships. The chemical defense due to PAs in Arctiidae moths and butterflies of sub-families Danainae and Ithomiinae (Nymphalidae) has been investigated with regards to vertebrate and invertebra
Publicado em: 2000
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4. Aplicação da ressonancia magnetica nuclear de carbono-13 na analise conformacional e determinação estrutural de alcaloides bisbenzilisoquinolinas
An analysis of C NMR of five series of bisbenzylisoquinoline alkaloids was carried out and the chemical shifts of more than forty compounds were assigned. The viability of the Birch reaction in the structure determination of Repanduline 3 and Dieline 4 was also undertaked. For this purpose three diphenyl-ethers models were synthesized and submitted to metal
Publicado em: 1982
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5. An unusual structural motif of antimicrobial peptides containing end-to-end macrocycle and cystine-knot disulfides
Four macrocyclic cystine-knot peptides of 29–31 residues, kalata, circulin A and B (CirA and CirB), and cyclopsychotride, have been isolated from coffee plants but have undetermined physiological functions. These macrocycles and 10 of their analogs prepared by chemical synthesis were tested against nine strains of microbes. Kalata and CirA were specific fo
The National Academy of Sciences.
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6. Structures of microfilament destabilizing toxins bound to actin provide insight into toxin design and activity
Marine macrolides that disrupt the actin cytoskeleton are promising candidates for cancer treatment. Here, we present the actin-bound x-ray crystal structures of reidispongiolide A and C and sphinxolide B, three marine macrolides found among a recently discovered family of cytotoxic compounds. Their structures allow unequivocal assignment of the absolute con
National Academy of Sciences.
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7. Molecular basis for the inhibition of human alpha-thrombin by the macrocyclic peptide cyclotheonamide A.
The macrocyclic peptide cyclotheonamide A (CtA), isolated from the marine sponge Theonella sp., represents an unusual class of serine protease inhibitor. A complex of this inhibitor with human alpha-thrombin, a protease central to the bioregulation of thrombosis and hemostasis, was studied by x-ray crystallography. This work (2.3-A resolution) confirms the s
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8. Structural flexibility of a DNA hairpin located in the long terminal repeat of the Drosophila 1731 retrotransposon.
The structure of the DNA binding site of the Nuclear single-stranded Binding Factor (NssBF), located in the long terminal repeat of the Drosophila 1731 retrotransposon, was investigated by melting temperature experiments, chemical probing and fluorescence measurements using a macrocyclic bis-acridine. The most probable structure of this element, named Bc, ma
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9. Grahamimycins: antibiotics from Cytospora sp. Ehrenb. W.F.P.L. 13A.
Aerobic fermentation of cultures of Cytospora sp. Ehrenb. W.F.P.L. 13A produces a group of novel, broad-spectrum, dilactone, macrocyclic antibiotics. These compounds, named grahamimycins, were isolated from the culture medium by extraction with organic solvents and separated by chromatography. Three active components have been obtained in crystalline form an
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10. Biomimetic macrocyclic receptors for carboxylate anion recognition based on C-linked peptidocalix[4]arenes
Two neutral macrobicyclic anion receptors 4 and 6, containing a calix[4]arene in the cone conformation, two l-alanine units, and a 2,6-diacylpyridine or a phthaloyl bridge, are described. The x-ray crystal structure of the acetone complexes of the pyridine containing macrocycle 6 shows the four amide NH groups to be in close proximity to the chiral pocket de
National Academy of Sciences.
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11. Dominant/recessive behavior in the expression of molecular information: Self-assembly of inorganic macrocyclic architectures containing coordinatively unsaturated ligands
The polytopic ligand 1 contains three different metal ion binding subunits forming two substructures that code for the self-assembly of two different coordination structures (helicate and grid type) under metal ion complexation. Reaction with Cu(II) and Zn(II) ions generates the coordinatively unsaturated architectures 8 and 9 resulting from the formation of
The National Academy of Sciences.
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12. Crystal structure of human uroporphyrinogen III synthase
Uroporphyrinogen III synthase, U3S, the fourth enzyme in the porphyrin biosynthetic pathway, catalyzes cyclization of the linear tetrapyrrole, hydroxymethylbilane, to the macrocyclic uroporphyrino gen III, which is used in several different pathways to form heme, siroheme, chlorophyll, F430 and vitamin B12. U3S activity is essential in all organisms, and d
Oxford University Press.