title: Conformational analysis of steroid hormone molecules in the lipid environment--a solid-state NMR approach.
abstract: Solid-state (1)H/(13)C cross-polarization/magic angle spinning (CP/MAS) NMR spectroscopy has been applied to two steroid compounds: dehydroepiandrosterone (DHEA) and spironolactone (SPI), to analyze their conformations at the atomic level. In the absence of lipid, the high-resolution (13)C CP/MAS NMR signals of DHEA and SPI in a powder form reveal multiple patterns, with splittings of 30-160 Hz, indicating the existence of multiple conformations. In the mimic lipid environment formed by mixing 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-diheptanoyl-sn-glycero-3-phosphocholine (DHPC) in a molar ratio 3:1, the resulting DHEA and SPI spectra revealed mostly singlet patterns, suggesting that these steroids undergo a conformational change leading to a specific conformation in the lipid environment. Evidence from chemical shift isotropy and anisotropy analysis indicates that DHEA might adopt conformations subtly different from that seen in solution and in the powder form. In conclusion, we demonstrate by solid-state NMR that the structures of DHEA and SPI may adopt slightly different conformations in different chemical environments.
authors.affiliation: Institute of Chemistry, Academia Sinica, 128, Yen-Chiu-Yuan Rd., Sec. 2, Nankang, Taipei 11529, Taiwan, ROC.
authors.forename: Ping-Chen
authors.initials: PC
authors.lastname: Shih
authors.forename: Guo-Chian
authors.initials: GC
authors.lastname: Li
authors.forename: Kai-Jay
authors.initials: KJ
authors.lastname: Yang
authors.forename: Wenlung
authors.initials: W
authors.lastname: Chen
authors.forename: Der-Lii M
authors.initials: DL
authors.lastname: Tzou
mesh_terms: D002247:Carbon Isotopes; D003687:Dehydroepiandrosterone / Q000737:chemistry* / Q000378:metabolism; D008055:Lipids / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008968:Molecular Conformation; D013148:Spironolactone / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002247:Carbon Isotopes; D008055:Lipids; D013148:Spironolactone; D003687:Dehydroepiandrosterone