Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10429225 | Tsinghua Science & Technology | 2005 | 8 Pages |
Abstract
Equilibrium guanidinium chloride (GdmCl)-induced unfolding of arginine kinase (AK) was investigated by enzymatic activity, intrinsic fluorescence, 8-anilinonaphthalene-1-sulfonic acid (ANS) fluorescence, circular dichroism (CD) spectrum, and size-exclusion chromatography. The measurements showed that AK unfolded through two equilibrium intermediates: the molten globule state and the partly folded state. Both intermediates have no enzyme activity. The molten globule state exists at 0.4-0.8 mol/L GdmCl, perhaps after the N-terminal domain has unfolded but the C-terminal domain is still intact. The partly folded state occurs at 1.1-1.5 mol/L GdmCl with a hydrodynamic volume no more than 1.6-fold larger than the native state and a pronounced far UV-CD signal. Its ANS fluorescence intensity is about 50% of the molten globule state. This partly folded state shares similarities with the “burst” kinetic intermediate of protein folding.
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Authors
Guo (éæç½¡), Xie (è°¢èè), Pan (æ½ç»§æ¿), Zhang (å¼ è£åº),