Remote Perturbations in Tertiary Contacts Trigger Ligation of Lysine to the Heme Iron in Cytochrome c.

ABSTRACT: Perturbations in protein structure define the mechanism of allosteric regulation and biological information transfer. In cytochrome c (cyt c), ligation of Met80 to the heme iron is critical for the protein's electron-transfer (ET) function in oxidative phosphorylation and for suppressing its peroxidase activity in apoptosis. The hard base Lys is a better match for the hard ferric iron than the soft base Met is, suggesting the key role of the protein scaffold in favoring Met ligation. To probe the role of the protein structure in the maintenance of Met ligation, mutations T49V and Y67R/M80A were designed to disrupt hydrogen bonding and packing of the heme coordination loop, respectively. Electronic absorption, nuclear magnetic resonance, and electron paramagnetic resonance spectra reveal th

SUBMITTER: Gu J 

PROVIDER: S-EPMC5647788 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature