Synthetic methodology that allows for incorporation of isotopic carbon at the C-3 and C-4 positions of bile salts is reported. Three [3,4-(13)C(2)]-enriched bile salts were synthesized from either deoxycholic or lithocholic acid. The steroid 3alpha-OH group was oxidized and the A-ring was converted into the Delta(4)-3-ketone. The C-24 carboxylic acid was next converted into the carbonate group and selectively reduced to the alcohol in the presence of the A-ring enone. Following protection of the 24-OH group, the Delta(4)-3-ketone was converted into the A-ring enol lactone. Condensation of the enol lactone with [1,2-(13)C(2)]-enriched acetyl chloride and subsequent Robinson annulation afforded a [3,4-(13)C(2)]-enriched Delta(4)-3-ketone that was subsequently converted back into a 3alpha-hydroxy-5beta-reduced bile steroid. C-7 hydroxylation, when necessary, was achieved via conversion of the Delta(4)-3-ketone into the corresponding Delta(4,6)-dien-3-one, epoxidation of the Delta(6)-double bond, and hydrogenolysis/hydrogenation of the 5,6-epoxy enone system. The [3,4-(13)C(2)]-enriched bile salts were subsequently complexed to human ileal bile acid binding protein (I-BABP), and (1)H-(13)C HSQC spectra were recorded to show the utility of the compounds for investigating the interactions of bile acids with I-BABP.
Protein-ligand docking guided by ligand pharmacophore-mapping experiment by NMR.
Protein-ligand docking guided by ligand pharmacophore-mapping experiment by NMR.
Protein-ligand docking guided by ligand pharmacophore-mapping experiment by NMR.
J Mol Graph Model. 2011 Sep 3;
Authors: Fukunishi Y, Mizukoshi Y, Takeuchi K, Shimada I, Takahashi H, Nakamura H
Abstract
We developed a new protein-ligand docking calculation method using experimental NMR data. Recently, we proposed a novel ligand epitope-mapping experiment, which utilizes the difference between the longitudinal relaxation rates of ligand protons with and...
Residual interactions in unfolded bile acid-binding protein by (19) F NMR.
Residual interactions in unfolded bile acid-binding protein by (19) F NMR.
Residual interactions in unfolded bile acid-binding protein by (19) F NMR.
Protein Sci. 2011 Feb;20(2):327-35
Authors: Basehore HK, Ropson IJ
The folding initiation mechanism of human bile acid-binding protein (BABP) has been examined by (19) F NMR. Equilibrium unfolding studies of BABP labeled with fluorine at all eight of its phenylalanine residues showed that at least two sites experience changes in solvent exposure at high denaturant concentrations. Peak...
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Residual interactions in unfolded bile acid-binding protein by (19)F-NMR.
Residual interactions in unfolded bile acid-binding protein by (19)F-NMR.
Related Articles Residual interactions in unfolded bile acid-binding protein by (19)F-NMR.
Protein Sci. 2010 Nov 29;
Authors: Basehore HK, Ropson IJ
The folding initiation mechanism of human bile acid-binding protein (BABP) has been examined by (19)F-NMR. Equilibrium unfolding studies of BABP labeled with fluorine at all eight of its phenylalanine residues showed that at least two sites experience changes in solvent exposure at high denaturant concentrations. Peak assignments...
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12-01-2010 04:41 PM
[NMR paper] A simple efficient synthesis of [23,24]-(13)C(2)-labeled bile salts as NMR probes of
A simple efficient synthesis of -(13)C(2)-labeled bile salts as NMR probes of protein-ligand interactions.
Related Articles A simple efficient synthesis of -(13)C(2)-labeled bile salts as NMR probes of protein-ligand interactions.
Bioorg Med Chem Lett. 2002 Feb 11;12(3):433-5
Authors: Tochtrop GP, DeKoster GT, Cistola DP, Covey DF
The synthesis of -(13)C(2)-labeled bile salts is achieved through a steroidal side chain degradation and isotopic regeneration strategy. Three common bile acids were degraded to the corresponding C(22 )aldehyde by an...
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[NMR paper] The inter-ligand Overhauser effect: a powerful new NMR approach for mapping structura
The inter-ligand Overhauser effect: a powerful new NMR approach for mapping structural relationships of macromolecular ligands.
Related Articles The inter-ligand Overhauser effect: a powerful new NMR approach for mapping structural relationships of macromolecular ligands.
J Biomol NMR. 1999 Sep;15(1):71-6
Authors: Li D, DeRose EF, London RE
NMR experiments that transfer conformational information from the bound to the uncomplexed state via exchange have been utilized for many years. It is demonstrated here that inter-ligand NOEs ('ILOEs'),...
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11-18-2010 08:31 PM
[NMR paper] H NMR probes for inter-segmental hydrogen bonds in myoglobins.
H NMR probes for inter-segmental hydrogen bonds in myoglobins.
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J Biochem. 1996 Jul;120(1):126-32
Authors: Yamamoto Y
NMR signals arising from the HisB5 N delta H and HisEF5 N epsilon H protons in sperm whale skeletal and horse heart myoglobins have been located for the first time in the downfield shifted portion of the spectra. The shifts and hydrogen exchange rates indicate that these His imidazole ring NH protons are involved in the inter-segmental hydrogen bonds...
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08-22-2010 02:27 PM
[NMR paper] On the ligand-protein and ligand-flavin interactions in NADPH-adrenodoxin reductase a
On the ligand-protein and ligand-flavin interactions in NADPH-adrenodoxin reductase as studied by 31P- and 13C-NMR. Use of 13C-enriched FAD as a probe.
Related Articles On the ligand-protein and ligand-flavin interactions in NADPH-adrenodoxin reductase as studied by 31P- and 13C-NMR. Use of 13C-enriched FAD as a probe.
J Biochem. 1991 Jan;109(1):144-9
Authors: Fujii S, Nonaka Y, Okamoto M, Miura R
The interaction between 2',5'-ADP and NADPH-adrenodoxin reductase from bovine adrenocortical mitochondria was examined by titrating the enzyme with...
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Synthesis of [3,4-(13)c(2)]-enriched bile salts as NMR probes of protein-ligand inter
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