To investigate protein folding dynamics in terms of compactness, we developed a continuous-flow mixing device to make smallangle x-ray scattering measurements with the time resolution of 160 μs and characterized the radius of gyration (Rg) of two folding intermediates of cytochrome c (cyt c). The early intermediate possesses ≈-20 Å of Rg, which is smaller by ≈-4 A than that of the acid-unfolded state. The Rg of the later intermediate is ≈-18 Å, which is close to that of the molten globule state. Considering the α-helix content (fH) of the intermediates, we clarified the folding pathway of cyt c on the conformational landscape defined by Rg and fH- Cyt c folding proceeds with a collapse around a specific region of the protein followed by a cooperative acquisition of secondary structures and compactness.
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - 2002 Feb 5|
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