A ring-shaped hemoprotein trimer thermodynamically controlled by the supramolecular heme-heme pocket interaction

Engineered cytochrome b 562 , a small hemoprotein, with an externally-attached heme moiety via a moderately long linker at a suitable position predominantly forms a thermodynamically stable ring-shaped trimer in dilute solution. In an equilibrium between supramolecular polymerization and depolymerization, the ring-shaped trimer is kinetically trapped even in a concentrated solution. A thermodynamically controlled supramolecular assembling system of cytochrome b 562 predominantly forms a ring-shaped trimer in dilute solution.