Further Studies on the Biosynthesis of Granaticin

Abstract Experiments with cerulenin-inhibited cultures of 5. violaceoruber showed conversion of dihydrogranaticin (II) into granaticin (I), but not vice versa, confirming an earlier conclusion that II is the biosynthetic precursor of I. Feeding of CH313C18O2Na followed by 13C-NMR analysis of the product by the 18O shift method indicated the expected incorporation of 18O at carbons 1,11 and 13 of I and showed that the oxygen of the pyran ring originates from C-3 and not from C-15. Analysis of I biosynthesized from 13C2H3COONa by 13C{1H, 2H} triple resonance NMR spectroscopy showed the incorporation of one atom of deuterium each at C-2 and C-4. C-16 carried a maximum of 2, not 3, atoms of deuterium. These results are discussed in terms of biosynthetic mechanisms.

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Turn-on Detection of Targeted Biochemical Reactions by Triple Resonance NMR Analysis Using Isotope-labeled Probe

Chemistry Letters ◽

10.1246/cl.2010.926 ◽

2010 ◽

Vol 39 (9) ◽

pp. 926-928 ◽

Cited By ~ 7

Author(s):

Keigo Mizusawa ◽

Ryuji Igarashi ◽

Kosei Uehira ◽

Yoshimasa Takafuji ◽

Yasuhiko Tabata ◽

...

Keyword(s):

Triple Resonance ◽

Triple Resonance Nmr ◽

Nmr Analysis ◽

Biochemical Reactions ◽

Turn On ◽

Labeled Probe

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Synthesis and Structure Assignment of 2-(4-Methoxybenzyl)cyclohexyl β-D-Glucopyranoside Enantiomers

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20061470 ◽

2006 ◽

Vol 71 (10) ◽

pp. 1470-1483 ◽

Cited By ~ 3

Author(s):

David Šaman ◽

Pavel Kratina ◽

Jitka Moravcová ◽

Martina Wimmerová ◽

Zdeněk Wimmer

Keyword(s):

Analytical Data ◽

Chiral Hplc ◽

Nmr Analysis ◽

Target Structure ◽

Enantiomerically Pure ◽

Whole Cells ◽

H Nmr ◽

Structure Assignment ◽

Related Compounds ◽

C Nmr

Glucosylation of the cis- and trans-isomers of 2-(4-methoxybenzyl)cyclohexan-1-ol (1a/1b, 2a/2b, 1a or 2a) was performed to prepare the corresponding alkyl β-D-glucopyranosides, mainly to get analytical data of pure enantiomers of the glucosides (3a-6b), required for subsequent investigations of related compounds with biological activity. One of the employed modifications of the Koenigs-Knorr synthesis resulted in achieving 85-95% yields of pure β-anomers 3a/3b, 4a/4b, 3a or 4a of protected intermediates, with several promoters and toluene as solvent, yielding finally the deprotected products 5a/5b, 6a/6b, 5a or 6a as pure β-anomers. To obtain enantiomerically pure β-anomers of the target structure (3a, 4a, 5a and 6a) for unambiguous structure assignment, an enzymic reduction of 2-(4-methoxybenzyl)cyclohexan-1-one by Saccharomyces cerevisiae whole cells was performed to get (1S,2S)- and (1S,2R)-enantiomers (1a and 2a) of 2-(4-methoxybenzyl)cyclohexan-1-ol. The opposite enantiomers of alkyl β-D-glucopyranosides (5b and 6b) were obtained by separation of the diastereoisomeric mixtures 5a/5b and 6a/6b by chiral HPLC. All stereoisomers of the products (3a-6b) were subjected to a detailed 1H NMR and 13C NMR analysis.

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NMR spectroscopy of poly(vinyl chloride) defects. 2. 1 H and 13 C NMR analysis of the terminal vinyl end group, 1,3-dichlorobutyl end group and chloromethyl branch

Macromolecular Symposia ◽

10.1002/masy.19940860107 ◽

1994 ◽

Vol 86 (1) ◽

pp. 65-75 ◽

Cited By ~ 7

Author(s):

George M. Benedikt ◽

Brian L. Goodall ◽

Larry F. Rhodes ◽

Alan C Kemball

Keyword(s):

Nmr Spectroscopy ◽

Vinyl Chloride ◽

Nmr Analysis ◽

Poly Vinyl Chloride ◽

End Group ◽

C Nmr

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Phage display-derived ligands provide structural insight into insulin-like growth factor I function

Spectroscopy An International Journal ◽

10.1155/2004/142593 ◽

2004 ◽

Vol 18 (2) ◽

pp. 237-249

Author(s):

Nicholas J. Skelton ◽

Michelle L. Schaffer ◽

Kurt Deshayes ◽

Tamas Blandl ◽

Steven Runyon ◽

...

Keyword(s):

Growth Factor ◽

Phage Display ◽

Binding Proteins ◽

Cell Surface Receptor ◽

Triple Resonance ◽

Triple Resonance Nmr ◽

Insulin Like Growth Factor ◽

Factor I ◽

Igf I ◽

Growth Factor I

Insulin–like growth factor–I (IGF–I) is a central mediator of cell growth, differentiation and metabolism. Structural characterization of the protein has been hampered by a combination of internal dynamics and self–association that prevent crystallization and produce broad NMR resonances. To better characterize the functions of IGF–I, we have used phage display to identify peptides that antagonize the binding of IGF–I to its plasma binding proteins (IGFBPs) and cell–surface receptor (IGF–R). Interestingly, binding of peptide improves dramatically the quality of the NMR resonances of IGF–I, and enables the use of triple–resonance NMR methods to characterize the complexes. One such peptide, designated IGF–F1–1, has been studied in detail. In the complex, the peptide retains the same loop–helix motif seen in the free state whilst IGF–I contains three helices, as has been seen previously in low–resolution structures in the absence of ligand. The peptide binds at a hydrophobic patch between helix 1 and 3, a site identified previously by mutagenesis as a contact site for IGFBP1. Thus, antagonism of IGFBP1 binding exhibited by the peptide occurs by a simple steric occlusion mechanism. Antagonism of IGF–R binding may also be explained by a similar mechanism if receptor binding occurs by a two–site process, as has been postulated for insulin binding to its receptor. Comparisons with crystallographic structures determined for IGF–I in other complexes suggest that the region around helix 1 of IGF–I is conformationally conserved whereas the region around helix 3 adopts several different ligand–induced conformations. The ligand–induced structural variability of helix 3 appears to be a common feature across the insulin super–family. In the case of IGF–I, exchange between such conformations may be the source of the dynamic nature of free IGF–I, and likely has functional significance for the ability of IGF–I to recognize two signaling receptors and six binding proteins with high affinity.

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Biosynthesis of Isoflavonoid Phytoalexins: Incorporation of Sodium [1,2-13C2] Acetate into Phaseollin and Kievitone

Zeitschrift für Naturforschung C ◽

10.1515/znc-1982-5-603 ◽

1982 ◽

Vol 37 (5-6) ◽

pp. 363-368 ◽

Cited By ~ 27

Author(s):

Paul M. Dewick ◽

Melanie J. Steele ◽

Richard A. Dixon ◽

Ian M. Whitehead

Keyword(s):

Phaseolus Vulgaris ◽

Nmr Analysis ◽

Polyketide Chain ◽

C Nmr

Abstract13C-NMR analysis of the isoflavonoid phytoalexins phaseollin and kievitone produced by feeding sodium [1,2-13C2]acetate to wounded bean (Phaseolus vulgaris) cotyledons has demonstrated the incorporation of intact acetate units into the aromatic A rings. Phaseollin shows a specific folding of the polyketide chain, whereas kievitone exhibits a randomisation of label in accordance with the intermediacy of a 2′,4′,6′-trihydroxylated chalcone during its formation. In neither case was sufficient label incorporated into analysis.

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