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Eur. J. Mass Spectrom. 8, 381 - 387 (2002) |
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A mass spectrometry investigation of the conformational changes in adrenocorticotropic hormones | ||
Hui Lin and Chhabil Dass* |
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ABSTRACT: | ||
Electrospray ionization-mass spectrometry (ESI-MS) was employed to study methanol-induced conformational changes in adrenocorticotrophic hormone (ACTH). ACTH, a 39-residue peptide, is a member of the proopiomelanocortin family of peptides. Charge-state distribution (CSD) and hydrogendeuterium (H/D) exchange were used to monitor the conformational changes as a function of methanol concentration. The latter experiments were conducted via time-resolved ESI-MS in a continuous-flow apparatus. The CSD and the H/D exchange experimental data both reveal that ACTH exists, presumably in a random coil open structure in aqueous media, but assumes a more compact helical conformation with increased concentration of methanol. The H/D exchange experiments also reveal that 79% of ACTH is present as a-helix in mixed water-methanol solvent media. | ||
Keywords: ACTH, conformation, ESI-MS, H/D exchange, charge-state distribution |
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