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Open-Bundle Structure as the Unfolding Intermediate of Cytochrome c' Revealed by Small Angle Neutron Scattering.

ABSTRACT: The dynamic structure changes, including the unfolding, dimerization, and transition from the compact to the open-bundle unfolding intermediate structure of Cyt c', were detected by a small-angle neutron scattering experiment (SANS). The structure of Cyt c' was changed into an unstructured random coil at pD = 1.7 (R_g = 25 Å for the Cyt c' monomer). The four-α-helix bundle structure of Cyt c' at neutral pH was transitioned to an open-bundle structure (at pD ~13), which is given by a numerical partial scattering function analysis as a joint-clubs model consisting of four clubs (α-helices) connected by short loops. The compactly folded structure of Cyt c' (radius of gyration, R_g = 18 Å for the Cyt c' dimer) at neutral or mildly alkaline pD transited to a remarkably larger open-bundle structure at pD ~13 (R_g = 25 Å for the Cyt c' monomer). The open-bundle structure was also supported by ab initio modeling.

SUBMITTER: Yamaguchi T

PROVIDER: S-EPMC8774185 | biostudies-literature |

REPOSITORIES: biostudies-literature

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