title: Compact molten globule-like state of hUBF HMG Box1 at extremely low pH.
abstract: 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.
authors.affiliation: School of Life Science, University of Science and Technology of China, People's Republic of China.
authors.forename: Xuecheng
authors.initials: X
authors.lastname: Zhang
authors.forename: Jiahai
authors.initials: J
authors.lastname: Zhang
authors.forename: Xuan
authors.initials: X
authors.lastname: Li
authors.forename: Junjie
authors.initials: J
authors.lastname: Xu
authors.forename: Hongda
authors.initials: H
authors.lastname: Huang
authors.forename: Quan
authors.initials: Q
authors.lastname: Chen
authors.forename: Jihui
authors.initials: J
authors.lastname: Wu
authors.forename: Yunyu
authors.initials: Y
authors.lastname: Shi
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000737:chemistry; D002942:Circular Dichroism; D005456:Fluorescent Dyes / Q000737:chemistry; D019791:Guanidine / Q000737:chemistry; D024742:HMG-Box Domains; D006609:High Mobility Group Proteins / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019906:Nuclear Magnetic Resonance, Biomolecular; D035463:Pol1 Transcription Initiation Complex Proteins / Q000737:chemistry*; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D013696:Temperature
chemical_list: D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D006609:High Mobility Group Proteins; D035463:Pol1 Transcription Initiation Complex Proteins; C063844:transcription factor UBF; C027132:1-anilino-8-naphthalenesulfonate; D019791:Guanidine