Compact molten globule-like state of hUBF HMG Box1 at extremely low pH

✍ Scribed by Xuecheng Zhang; Jiahai Zhang; Xuan Li; Junjie Xu; Hongda Huang; Quan Chen; Jihui Wu; Yunyu Shi

• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 367 KB
• Volume: 1748
• Category: Article
• ISSN: 1570-9639
• DOI: 10.1016/j.bbapap.2004.12.002

✦ Synopsis

Using far and near-UV CD, ANS fluorescence and 2D NMR spectroscopy, an acid-induced partly folded state (A state) at extremely low pH for hUBF HMG Box1 was identified and characterized. As compared to the native state (N), the A state has similar secondary structure, less compact pack with larger amounts of exposed hydrophobic surface, and narrower chemical shift dispersion in 1 H-15 N HSQC spectrum, which implies that it is a molten globule (MG)-like species. On the other hand, substantial tertiary contacts and cooperative thermal denaturing transition indicate that the A state is closer-relative to the classic MG-to the native folded state. In addition, when the solution pH is adjusted to neutrality, the protein in the A state refolds to the native state easily. All these data suggest that the A state of hUBF HMG Box1 could represent a potential folding intermediate on protein folding pathway.