title: Conformational changes in beta-endorphin as studied by electrospray ionization mass spectrometry.
abstract: Because of a wide range of physiological functions, the structure of beta-endorphin (BE) is of great interest. In this study, conformational changes in BE induced by methanol are explored with electrospray ionization-mass spectrometry (ESI-MS). Differences in the charge-state distribution (CSD) and the extent of hydrogen/deuterium (H/D) exchange were used to monitor the conformational changes. The latter experiments were conducted via time-resolved ESI-MS in a continuous-flow apparatus. Both these techniques demonstrate that BE exists in a random coil open structure in aqueous media, but it acquires a more compact conformation with increased concentration of methanol. The H/D exchange experiments reveal that BE forms 61% alpha-helix in mixed solvents.
authors.affiliation: Department of Chemistry, The University of Memphis, TN 38152, USA.
authors.forename: H
authors.initials: H
authors.lastname: Lin
authors.forename: C
authors.initials: C
authors.lastname: Dass
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003903:Deuterium / Q000737:chemistry; D004563:Electrochemistry; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D000432:Methanol; D017433:Protein Structure, Secondary; D021241:Spectrometry, Mass, Electrospray Ionization; D013696:Temperature; D001615:beta-Endorphin / Q000737:chemistry*
chemical_list: D001615:beta-Endorphin; D003903:Deuterium; D000432:Methanol