ISSN:
0899-0042
Keywords:
nuclear magnetic resonance
;
isotopically labelled proteins
;
drug-protein interactions
;
chiral interaction
;
calmodulin antagonism
;
chiral HPLC
;
(R) and (S) calmidazolium
;
Chemistry
;
Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Calmidazolium {R24571, 1-[bis(4-chlorophenyl)methyl]-3-[2-(2,4-dichlorophenyl)-2-[(2,4-dichlorophenyl)methoxy]ethyl]-1H-imidazolium chloride} is a potent calmodulin inhibitor. This paper describes the synthesis and properties of the enantiomers of calmidazolium from the enantiomers of miconazole {1(N)-(2-(2,4-dichlorobenzyloxy)-2-(2,4-dichlorophenyl))-ethyl imidazole}, prepared from the racemate by chiral preparative scale high performance liquid chromatography. Overlap between ligand and protein resonances in the aromatic region of the 1H NMR spectrum of the calmidazolium-calmodulin complexes has been obviated by preparation of the protein with all of its nine phenylalanine rings deuterated (Phe-d5 calmodulin). This has been accomplished by the overexpression of calmodulin derived from Trypanosoma brucei rhodiesiense in E. coli in a medium supplemented with ring-deuterated phenylalanine. The kinetics of binding of each enantiomer are slow on the 1H NMR time scale as judged by the behaviour of the H2 resonance of Histidine-107, which is clearly visible under the sample conditions used. The aromatic spectral regions of the protein-bound (+) and (-) enantiomers contrast strikingly, reflecting differences in bound environment and/or conformation. Chirality 8:545-500, 1996. © 1997 Wiley-Liss, Inc.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
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