Denatured collapsed states in protein folding: Example of apomyoglobin

Tcherkasskaya, O Uversky, VN

O. Tcherkasskaya et Vn. Uversky, Denatured collapsed states in protein folding: Example of apomyoglobin, PROTEINS, 44(3), 2001, pp. 244-254

89

INGLESE

Article

Biochemistry & Biophysics

PROTEINS-STRUCTURE FUNCTION AND GENETICS

0887-3585 → ACNP

44

3

2001

244 - 254

ISI

0887-3585(20010815)44:3<244:DCSIPF>2.0.ZU;2-J

Experimental approaches, including circular dichroism, small angle X-ray sc attering, steady-state fluorescence, and fluorescence energy transfer, were applied to study the 3D-structure of apomyolgobin in different conformatio nal states. These included the native and molten globules, along with eithe r less ordered conformations induced by the addition of anions or completel y unfolded states. The results show that the partially folded forms of apom yoglobin stabilized by KCl and/or Na2SO4 under unfolding conditions (pH 2) exhibit a significant amount of secondary structure (circular dichroism), l ow packing density of protein molecules (SAXS), and native-like dimensions of the AGH core (fluorescence energy transfer). This finding indicates that a native-like tertiary fold of the polypeptide chain, i.e., the spatial or ganization of secondary structure elements, most likely emerges prior to th e formation of the molten globule state. (C) 2001 Wiley-Liss, Inc.*