Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Complete stereochemistry of neamphamide A and absolute configuration of the beta-methoxytyrosine residue in papuamide B.

ABSTRACT: The absolute stereochemistry of the three unresolved structural components in neamphamide A (1) was determined to be (R)-beta-methoxy-L-tyrosine, (2R,3R,4S)-4-amino-7-guanidino-2,3-dihydroxyheptanoic acid, and (2R,3R,4R)-3-hydroxy-2,4,6-trimethylheptanoic acid. Stereochemical assignments were made by chemical degradation of 1, derivatization of the resulting products, and then spectroscopic and chromatographic comparison of the derivatives with synthetically prepared standards. Using the same analytical protocol developed for 1, the beta-methoxytyrosine residue in papuamide B (2) was found to be (R)-beta-methoxy-D-tyrosine. This represents a rare example of divergent stereochemistry in an unusual amino acid residue that is present in two closely related classes of peptides.

SUBMITTER: Oku N

PROVIDER: S-EPMC1513540 | biostudies-literature | 2005 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Complete stereochemistry of neamphamide A and absolute configuration of the beta-methoxytyrosine residue in papuamide B.

Oku Naoya N Krishnamoorthy Ravi R Benson Alan G AG Ferguson Robert L RL Lipton Mark A MA Phillips Lawrence R LR Gustafson Kirk R KR McMahon James B JB

The Journal of organic chemistry 20050801 17

The absolute stereochemistry of the three unresolved structural components in neamphamide A (1) was determined to be (R)-beta-methoxy-L-tyrosine, (2R,3R,4S)-4-amino-7-guanidino-2,3-dihydroxyheptanoic acid, and (2R,3R,4R)-3-hydroxy-2,4,6-trimethylheptanoic acid. Stereochemical assignments were made by chemical degradation of 1, derivatization of the resulting products, and then spectroscopic and chromatographic comparison of the derivatives with synthetically prepared standards. Using the same an ...[more]

PMID: 16095304

Similar Datasets

Progressive-convergent elucidation of stereochemistry in complex polyols. The absolute configuration of (-)-sagittamide A.

Project description:The absolute stereostructure of sagittamide A (1), a O-hexacetyl long-chain hexahydroxy-alpha,omega-dicarboxylic acid, was assigned using a progressive-convergent approach that integrates three powerful regimens for stereochemical analysis of acyclic natural products: J-based analysis, 13C NMR universal database comparisons, and exciton coupling circular dichroism.

| S-EPMC3340292 | biostudies-literature

Stereochemistry of Endogenous Palmitic Acid Ester of 9-Hydroxystearic Acid and Relevance of Absolute Configuration to Regulation.

Project description:Lipids have fundamental roles in the structure, energetics, and signaling of cells and organisms. The recent discovery of fatty acid esters of hydroxy fatty acids (FAHFAs), lipids with potent antidiabetic and anti-inflammatory activities, indicates that our understanding of the composition of lipidome and the function of lipids is incomplete. The ability to synthesize and test FAHFAs was critical in elucidating the roles of these lipids, but these studies were performed with racemic mixtures, and the role of stereochemistry remains unexplored. Here, we synthesized the R- and S- palmitic acid ester of 9-hydroxystearic acid (R-9-PAHSA, S-9-PAHSA). Access to highly enantioenriched PAHSAs enabled the development of a liquid chromatography-mass spectrometry (LC-MS) method to separate and quantify R- and S-9-PAHSA, and this approach identified R-9-PAHSA as the predominant stereoisomer that accumulates in adipose tissues from transgenic mice where FAHFAs were first discovered. Furthermore, biochemical analysis of 9-PAHSA biosynthesis and degradation indicate that the enzymes and pathways for PAHSA production are stereospecific, with cell lines favoring the production of R-9-PAHSA and carboxyl ester lipase (CEL), a PAHSA degradative enzyme, selectively hydrolyzing S-9-PAHSA. These studies highlight the role of stereochemistry in the production and degradation of PAHSAs and define the endogenous stereochemistry of 9-PAHSA in adipose tissue. This information will be useful in the identification and characterization of the pathway responsible for PAHSA biosynthesis, and access to enantiopure PAHSAs will elucidate the role of stereochemistry in PAHSA activity and metabolism in vivo.

| S-EPMC5568760 | biostudies-literature

Structure Revision of Poecillastrin C and the Absolute Configuration of the ?-Hydroxyaspartic Acid Residue.

Project description:The planar structure of poecillastrin C (1) was revised through selective reduction of the ester carbon. The absolute configuration of the ?-hydroxyaspartic acid (OHAsp) residue was determined to be d-threo by Marfey's analysis. The acid hydrolysate of the reduction product of 1 liberated (2R,3R)-2-amino-3,4-dihydroxybutanoic acid, demonstrating that the ?-carboxyl group in poecillastrin C was esterified. The structures of poecillastrins B-D and 73-deoxychondropsin A were also revised.

| S-EPMC6325643 | biostudies-literature

Assignment of the C5' relative stereochemistry in (+)-lepadin F and (+)-lepadin G and absolute configuration of (+)-lepadin G.

Project description:Concise assignments of the C5' stereochemistry in (+)-lepadin F and (+)-lepadin G and the absolute configuration of (+)-lepadin G via the first total syntheses of (+)-5'-epi-lepadin F, (+)-lepadin G, and (+)-5'-epi-lepadin G are described. This work represents an illustrative example in which a diastereomeric pair can possess sufficient spectroscopic difference for clear assignment despite differing only at a highly insulated acyclic stereocenter.

| S-EPMC2822462 | biostudies-literature

Absolute configuration of odorine.

Project description:The title compound, known as odorine or roxburghiline {systematic name: (S)-N-[(R)-1-cinnamoylpyrrolidin-2-yl]-2-methyl-butanamide}, C(18)H(24)N(2)O(2), is a nitro-genous compound isolated from the leaves of Aglaia odorata. The absolute configuration was determined by refinement of the Flack parameter with data collected using Cu Kα radiation showing positions 2 and 2' to be S and R, respectively. The pyrrolidine ring adopts an envelope conformation. In the crystal, mol-ecules are linked into chains along [010] by inter-molecular N-H⋯O hydrogen bonds.

| S-EPMC3007931 | biostudies-literature

Synthesis, Absolute Configuration, Antibacterial, and Antifungal Activities of Novel Benzofuryl β-Amino Alcohols.

Project description:A series of new benzofuryl α-azole ketones was synthesized and reduced by asymmetric transfer hydrogenation (ATH). Novel benzofuryl β-amino alcohols bearing an imidazolyl and triazolyl substituents were obtained with excellent enantioselectivity (96-99%). The absolute configuration (R) of the products was confirmed by means of electronic circular dichroism (ECD) spectroscopy supported by theoretical calculations. Selected benzofuryl α-azole ketones were also successfully asymmetrically bioreduced by fungi of Saccharomyces cerevisiae and Aureobasidium pullulans species. Racemic and chiral β-amino alcohols, as well as benzofuryl α-amino and α-bromo ketones were evaluated for their antibacterial and antifungal activities. From among the synthesized β-amino alcohols, the highest antimicrobial activity was found for (R)-1-(3,5-dimethylbenzofuran-2-yl)-2-(1H-imidazol-1-yl)ethan-1-ol against S. aureus ATCC 25923 (MIC = 64, MBC = 96 μg mL-1) and (R)-1-(3,5-dimethylbenzofuran-2-yl)-2-(1H-1,2,4-triazol-1-yl)ethan-1-ol against yeasts of M. furfur DSM 6170 (MIC = MBC = 64 μg mL-1). In turn, from among the tested ketones, 1-(benzofuran-2-yl)-2-bromoethanones (1-4) were found to be the most active against M. furfur DSM 6170 (MIC = MBC = 1.5 μg mL-1) (MIC-minimal inhibitory concentration, MBC-minimal biocidal concentration).

| S-EPMC7560283 | biostudies-literature

Absolute configuration of isoeichlerialactone.

Project description:The title seco-dammarane triterpenoid, C(27)H(42)O(4) (systematic name: 3-{(3S,3aR,5aR,6S,7S,9aR,9bR)-6,9a,9b-trimethyl-3-[(R)-2-methyl-5-oxotetra-hydro-furan-2-yl]-7-(prop-1-en-2-yl)dodeca-hydro-1H-cyclo-penta-[a]naphthalen-6-yl}propanoic acid), has been isolated for the first time from the seeds of Aglaia forbesii. The mol-ecule has three fused rings and all rings are in trans-fused. The two cyclo-hexane rings are in standard chair conformations and the cyclo-pentane ring adopts an envelope conformation. Its absolute configuration was determined by the refinement of the Flack parameter to 0.26?(17). In the crystal, mol-ecules are linked into chains along [010] by O-H?O hydrogen bonds.

| S-EPMC2984085 | biostudies-other

Absolute configuration of micromelin.

Project description:The title compound {systematic name: 7-meth-oxy-6-[(1R,2R,5R)-5-methyl-4-oxo-3,6-dioxabicyclo-[3.1.0]hexan-2-yl]-2H-chromen-2-one}, C(15)H(12)O(6), is a coumarin, which was isolated from the roots of Micromelum glanduliferum. There are two mol-ecules in the asymmetric unit with slight differences in bond angles. In both mol-ecules, the furan ring adopts a flattened envelope conformation. In the crystal, mol-ecules are linked by weak C-H?O inter-actions into chains along the a axis. Aromatic ?-? stacking inter-actions with centroid-centroid distances in the range 3.6995?(11)-3.8069?(11)?Å and C?O short contacts [3.030?(2)-3.171?(3)?Å] also occur.

| S-EPMC3151812 | biostudies-other

Absolute configuration of dolichol.

Project description:A derivative of dolichol was formed and then chemically degraded to a small fragment containing the sole centre of asymmetry of the original molecule. Polarimetric comparison of this derivative with a standard prepared from (R)-citronellol showed dolichol to have an S-configuration at C-3. To determine the optical purity of dolichol a diastereoisomeric derivative was prepared and compared with standard diastereoisomers, which could be resolved by high-pressure liquid chromatography. Dolichols from pig liver, human liver and hen oviduct were analysed by this procedure and were all found to be greater than 95% S-configuration.

| S-EPMC1162022 | biostudies-other

Absolute configuration of fibaruretin B.

Project description:The title furan-oditerpenoid, known as fibaruretin B (systematic name: 2?,3?-dihy-droxy-2,3,7,8?-tetra-hydro-penianthic acid lactone), C(20)H(24)O(7), was isolated from the roots of Arcangelisia flava. The absolute configurations at positions 2, 3, 4, 4a, 7, 9, 10a and 10b of fibaruretin B are S, R, S, R, S, S, S and S, respectively. In the crystal structure, the mol-ecules are linked into infinite chains along the c axis by O-H?O hydrogen bonds and weak C-H?O inter-actions.

| S-EPMC3089215 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data