NMR assignments of tryptophan residue in apo and holo LBD-rVDR

Wanda Sicinska, William M. Westler, Hector F. DeLuca
2005 Proteins: Structure, Function, and Bioinformatics  
Binding sites in the full-length, ligand-binding domain of rat vitamin D receptor (LBD-rVDR) for an active hormone derived from vitamin D (1␣,25-dihydroxyvitamin D 3 ) and three of its C-2 substituted analogs were compared by nuclear magnetic resonance (NMR) spectroscopy. Specific residue labeled with [UL]-15 N 2 Trp allowed assignment of the side-chain H ⑀1 and N ⑀1 resonances of the single tryptophan residue at position 282 in LBD-rVDR. Comparison of 1 H[ 15 N] Heteronuclear Single Quantum
more » ... relation (HSQC) spectra of apo and holo LBD-rVDR revealed that the position of the Trp282 H ⑀1 and N ⑀1 signals are sensitive to the presence of the ligand in the receptor cavity. Binding of the ligands to LBD-rVDR results in a shift of both Trp H ⑀1 and N ⑀1 resonances to lower frequencies. The results indicate that the interaction between the ligands and Trp282 is not responsible for differences in calcemic activity observed in vitamin D analogs. Proteins 2005;61:461-467.
doi:10.1002/prot.20625 pmid:16130132 fatcat:ikwnvzlcofetllxnvsdc5jh5ay