Formation of an alpha-helix in human tumor necrosis factor-alpha by guanidine hydrochloride-induced unfolding |
| |
Authors: | Jeong Woojin Shin Hang-Cheol |
| |
Institution: | Department of Bioinformatics and Life Science, and Computer-Aided Molecular Design Research Center, Soongsil University, Seoul 156-743, Korea. |
| |
Abstract: | Human tumor necrosis factor-alpha (TNF-alpha) is a trimeric protein consisting primarily of beta-sheet. GdnHCl-induced unfolding of TNF-alpha was investigated at room temperature by circular dichroism (CD) and size exclusion chromatography. The secondary and tertiary structure of TNF-alpha persisted up to 0.9N GdnHCl regardless of incubation time, but, in the range of 1.2 N to 2.1 N GdnHCl, there was loss of tertiary structure accompanied by the formation of an alpha-helix, as revealed by far- and near-UV CD spectra. The structural changes occurred gradually in 1.2 and 2.1 N GdnHCl, but were rapid in 1.5 and 1.8 N GdnHCl. The GdnHCl-induced state of TNF-alpha is an unfolded, alpha-helical aggregate of about 130 monomers, as shown by size exclusion chromatography. We suggest the most likely pathway for the transition from beta-sheet to alpha-helix. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|