Heme binding constricts the conformational dynamics of the cytochrome b(559)' heme binding cavity.

Yasar Akdogan, Veerappan Anbazhagan, Dariush Hinderberger, Dirk Schneider

Institut für Pharmazie und Biochemie, Johannes Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 30, 55128 Mainz, Germany.

Biochemistry 2012 Sep 11

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Cytochrome b(559)' is a transmembrane protein formed by homodimerization of the 44-residue PsbF polypeptide and noncovalent binding of a heme cofactor. The PsbF polypeptide can dimerize in the absence and presence of heme. To monitor structural alterations associated with binding of heme to the apo-cytochrome, we analyzed the apo- and holo-cytochrome structure by electron paramagnetic resonance spectroscopy. Spin labeling of amino acids located close to the heme binding domain of the cytochrome revealed that the structure of the heme binding domain is unconstrained in the absence of heme. Heme binding restricts the conformational dynamics of the heme binding domain, resulting in the structurally more constricted holo-cytochrome structure.

Citation

Yasar Akdogan, Veerappan Anbazhagan, Dariush Hinderberger, Dirk Schneider. Heme binding constricts the conformational dynamics of the cytochrome b(559)' heme binding cavity. Biochemistry. 2012 Sep 11;51(36):7149-56