AMIDOMYCIN, A NEW ANTIBIOTIC FROM A STREPTOMYCES SPECIES, CHEMICAL STRUCTURE

Amidomycin, an antibiotic active primarily against yeast, has been isolated from a Streptomyces species. The Compound C10H68O12N4. is neutral, optically active, and shows no unsaturation nor characteristic light absorption maxima. It is composed of 4 moles each of D(−)-valine and D(−)-α-hydroxyisovaleric acid, linked alternately by ester and amide bonds to form a 24-membered ring (I). This structure is assigned from the following observations: on mild alkaline hydrolysis 4 moles of alkali are consumed with formation of a hydroxy acid, C10H19O4N (II). The latter on distillation gave a crystalline lactone, C10H17O3N, considered to be 3,6-diisopropyl-2,5-diketomorpholine (III), which was hydrolyzed to give 1 mole each of D(−)-valine and D(−)-α-hydroxyisovaleric acid.Amidomycin is closely related to valinomycin, an antibiotic isolated from Streptomycesfulvissimus and shown to be a 24-membered ring compound containing D(−)-valine, D(−)-α-hydroxyisovaleric acid, L(+)-valine, and L(−)-lactic acid. It also resembles the enniatins, produced by certain species of Fusarium, but differs from these compounds in the number of units in the ring structure as well as in containing D(−)-valine rather than an N-methyl-L-amino acid.

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Silica Surface Modification Reactions with Aluminum and Boron Alkyls and (Alkyl)Chlorides: Reactivities and Surface Nanostructures

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.c199 ◽

2008 ◽

Vol 8 (2) ◽

pp. 660-666 ◽

Cited By ~ 4

Author(s):

Jonathan P. Blitz ◽

Jeannine M. Christensen ◽

Carol A. Deakyne ◽

Vladimir M. Gun'ko

Keyword(s):

Chemical Structure ◽

Silica Surface ◽

Molecular Level ◽

Ring Structure ◽

Membered Ring ◽

Silica Surfaces ◽

Surface Nanostructures ◽

Reactive Groups ◽

Aluminum Compounds ◽

Silica Surface Modification

The functionalization of nanoporous and nanoparticulate silica surfaces requires a molecular level understanding of the chemistry and structures which result from surface reactions. Various types of reactive groups on silica can participate, giving rise to different nanostructures. It is necessary to devise methods to alter the reactive nature of silica surfaces to control the nanoscale chemical structure. Various silica pretreatments are utilized to alter the silica surface prior to reaction with AlEt3, AlEtxCl3−x, BEt3, BCl3, and TiCl4. Reactivities of these surface reactive reagents are compared. Aluminum compounds preferentially react with loss of alkane rather than HCl, in a thermodynamically controlled reaction as determined by ab initio computational methods. Consideration of the structures resulting from reaction of the boron and aluminum compounds above with silica surface diols has been taken into account. Particular attention has been paid to the possibility of forming a cyclic 4-membered ring structure. While this is unlikely to form from reactions with MCl3, such structures may be possible when reacting silicas with MMe3.

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An asymmetric synthesis of carboxylic acid derivatives, including lactic acid and α-amino acid derivatives, from optically active 1-chlorovinyl p-tolyl sulfoxides and ester lithium enolates with creation of chirality at the α-position

Tetrahedron Asymmetry ◽

10.1016/j.tetasy.2007.07.033 ◽

2007 ◽

Vol 18 (16) ◽

pp. 1934-1947 ◽

Cited By ~ 9

Author(s):

Masahiro Kido ◽

Shimpei Sugiyama ◽

Tsuyoshi Satoh

Keyword(s):

Lactic Acid ◽

Amino Acid ◽

Carboxylic Acid ◽

Asymmetric Synthesis ◽

Optically Active ◽

Amino Acid Derivatives ◽

Lithium Enolates

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Immunoelectron microscope detection of C-type natriuretic peptide in normal human atrial tissue

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100147776 ◽

1993 ◽

Vol 51 ◽

pp. 388-389

Author(s):

Chi-Ming Wei ◽

Margaret Hukee ◽

Christopher G.A. McGregor ◽

John C. Burnett

Keyword(s):

Amino Acid ◽

Natriuretic Peptide ◽

Vascular Tone ◽

Cardiac Tissue ◽

Ring Structure ◽

Terminal Amino Acid ◽

Amino Acid Peptide ◽

Normal Human ◽

Terminal Amino ◽

The Brain

C-type natriuretic peptide (CNP) is a newly identified peptide that is structurally related to atrial (ANP) and brain natriuretic peptide (BNP). CNP exists as a 22-amino acid peptide and like ANP and BNP has a 17-amino acid ring formed by a disulfide bond. Unlike these two previously identified cardiac peptides, CNP lacks the COOH-terminal amino acid extension from the ring structure. ANP, BNP and CNP decrease cardiac preload, but unlike ANP and BNP, CNP is not natriuretic. While ANP and BNP have been localized to the heart, recent investigations have failed to detect CNP mRNA in the myocardium although small concentrations of CNP are detectable in the porcine myocardium. While originally localized to the brain, recent investigations have localized CNP to endothelial cells consistent with a paracrine role for CNP in the control of vascular tone. While CNP has been detected in cardiac tissue by radioimmunoassay, no studies have demonstrated CNP localization in normal human heart by immunoelectron microscopy.

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Changes of Antioxidant Activity and the Isoflavone and Free Amino Acid Content of Fermented Tofu with Kimchi Ingredients and Lactic Acid Bacteria

Journal of the Korean Society of Food Science and Nutrition ◽

10.3746/jkfn.2013.42.1.096 ◽

2013 ◽

Vol 42 (1) ◽

pp. 96-101 ◽

Cited By ~ 1

Author(s):

Kyoung-Myoung Kang ◽

Shin-Ho Lee

Keyword(s):

Antioxidant Activity ◽

Lactic Acid ◽

Amino Acid ◽

Lactic Acid Bacteria ◽

Free Amino Acid ◽

Acid Content ◽

Free Amino ◽

Amino Acid Content ◽

Free Amino Acid Content

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Effects of Inoculating Compound Lactic Acid Bacteria on the Quality of Cured Fish

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.685.486 ◽

2014 ◽

Vol 685 ◽

pp. 486-489 ◽

Cited By ~ 1

Author(s):

Yan Yan Wu ◽

Gang You ◽

Lai Hao Li ◽

Xian Qing Yang ◽

Ya Wei

Keyword(s):

Lactic Acid ◽

Amino Acid ◽

Lactic Acid Bacteria ◽

Nitrogen Content ◽

Acid Content ◽

Total Acid ◽

Fish Quality ◽

Salted Fish ◽

Positive Effects ◽

Amino Acid Nitrogen

Inoculation with compound lactobacillus in the low-salt pickled fish, fermented and dried to produce cured fish. The paper studied the effects of inoculating compound lactobacillus on the pH, total volatile basic nitrogen (TVB-N), amino acid nitrogen content (AA-N) and total acid content of salted fish quality. The results showed that, compared with the non-vaccinated groups (CK), The cured fish inoculated lactobacillus had a lower pH and TVB-N content, higher the amino acid nitrogen content and total acid content. Inoculated compound lactic acid bacteria into salted fish, to a certain extent, could improve the nutritional value and edible value, which had positive effects on the fish quality.

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Understanding the microcrystal tests of three related phenethylamines: theortho-metallated (±)-amphetamine formed with gold(III) chloride, and the tetrachloridoaurate(III) salts of (+)-methamphetamine and (±)-ephedrine

Acta Crystallographica Section C Crystal Structure Communications ◽

10.1107/s0108270113006379 ◽

2013 ◽

Vol 69 (4) ◽

pp. 388-393 ◽

Cited By ~ 5

Author(s):

Matthew R. Wood ◽

Roger A. Lalancette

Keyword(s):

Drug Use ◽

Illicit Drug ◽

Illicit Drug Use ◽

Ring Structure ◽

Membered Ring ◽

Asymmetric Unit ◽

Organic Components ◽

Bidentate Complex

Theortho-metallation product of the reaction of (±)-amphetamine with gold(III) chloride, [D,L-2-(2-aminopropyl)phenyl-κ2N,C1]dichloridogold(III), [Au(C9H12N)Cl2], and the two salts resulting from crystallization of (+)-methamphetamine with gold(III) chloride, D-methyl(1-phenylpropan-2-yl)azanium tetrachloridoaurate(III), (C10H16N)[AuCl4], and of (±)-ephedrine with gold(III) chloride, D,L-(1-hydroxy-1-phenylpropan-2-yl)(methyl)azanium tetrachloridoaurate(III), (C10H16NO)[AuCl4], have different structures. The first makes a bidentate complex directly with a dichloridogold(III) group, forming a six-membered ring structure; the second and third each form a salt with [AuCl4]−(each has two formula units in the asymmetric unit). The organic components are all members of the same class of stimulants that are prevalent in illicit drug use. These structures are important contributions to the understanding of the microcrystal tests for these drugs that have been employed for well over 100 years.

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Structural and Functional Conversion of Molecular Chaperone ClpB from the Gram-Positive Halophilic Lactic Acid Bacterium Tetragenococcus halophilus Mediated by ATP and Stress

Journal of Bacteriology ◽

10.1128/jb.00404-06 ◽

2006 ◽

Vol 188 (23) ◽

pp. 8070-8078 ◽

Cited By ~ 17

Author(s):

Shinya Sugimoto ◽

Hiroyuki Yoshida ◽

Yoshimitsu Mizunoe ◽

Keigo Tsuruno ◽

Jiro Nakayama ◽

...

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacterium ◽

Molecular Chaperone ◽

Thermal Inactivation ◽

Gel Filtration ◽

Ring Structure ◽

Stress Conditions ◽

Gel Filtration Chromatography ◽

Gram Positive ◽

Tetragenococcus Halophilus

ABSTRACT In this study, we report the purification, initial structural characterization, and functional analysis of the molecular chaperone ClpB from the gram-positive, halophilic lactic acid bacterium Tetragenococcus halophilus. A recombinant T. halophilus ClpB (ClpB Tha ) was overexpressed in Escherichia coli and purified by affinity chromatography, hydroxyapatite chromatography, and gel filtration chromatography. As demonstrated by gel filtration chromatography, chemical cross-linking with glutaraldehyde, and electron microscopy, ClpB Tha forms a homohexameric single-ring structure in the presence of ATP under nonstress conditions. However, under stress conditions, such as high-temperature (>45°C) and high-salt concentrations (>1 M KCl), it dissociated into dimers and monomers, regardless of the presence of ATP. The hexameric ClpB Tha reactivated heat-aggregated proteins dependent upon the DnaK system from T. halophilus (KJE Tha ) and ATP. Interestingly, the mixture of dimer and monomer ClpB Tha , which was formed under stress conditions, protected substrate proteins from thermal inactivation and aggregation in a manner similar to those of general molecular chaperones. From these results, we hypothesize that ClpB Tha forms dimers and monomers to function as a holding chaperone under stress conditions, whereas it forms a hexamer ring to function as a disaggregating chaperone in cooperation with KJE Tha and ATP under poststress conditions.

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14,15-Didehydrohellebrigenin

Acta Crystallographica Section E Structure Reports Online ◽

10.1107/s1600536812018570 ◽

2012 ◽

Vol 68 (6) ◽

pp. o1614-o1615

Author(s):

Tong Yu ◽

Hai-Yan Tian ◽

Xiao-Feng Yuan ◽

Shu-Zhi Hu ◽

Ren-Wang Jiang

Keyword(s):

Hydrogen Bond ◽

Hydrogen Bonds ◽

Title Compound ◽

Lactone Ring ◽

Three Dimensional ◽

Membered Ring ◽

Envelope Conformation ◽

Compound C ◽

Dimensional Network ◽

Hydroxy Groups

The title compound, C24H30O5, is the didehydro product of the steroid hellebrigenin (systematic name: 3β,5,14-trihydroxy-19-oxo-5β-bufa-20,22-dienolide). It consists of three cyclohexane rings (A, B and C), a five-membered ring (D) and a six-membered lactone ring (E). The stereochemistry of the ring junctions are A/B cis, B/C trans and C/D cis. Cyclohexane rings A, B and C have normal chair conformations. The five-membered ring D with the C=C bond adopts an envelope conformation. Lactone ring E is essentially planar with a mean derivation of 0.006 (4) Å and is β-oriented at the C atom of ring D to which it is attached. There is an O—H...O hydrogen bond in the molecule involving the hydroxy groups. In the crystal, O—H...O hydrogen bonds link the molecules into chains propagating along [010]. The chains are linked by C—H...O contacts into a three-dimensional network.

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