The binding kinetics of heme and chlorins analogues to natural and de novo designed proteins is explained, uncovering the underlying engineering that governs molecular assembly.   We use protein maquettes with a variety of structural topologies, ranging from molten globular tetramers to natively structured monomers to illustrate how these aspects control the assembly. The temperature dependence reveals different kinetics depending on what type of protein topology or porphyrin/chlorin variant is used. Three important steps involved in this mechanism where protein structure can limit the rate: 1)Forming a binding site, 2)Allowing the porphyrin to partition into the protein's hydrophobic core, 3)The protein structure conforming around the porphyrin allowing it to form coordination bonds. Finally, the effect of the porphyrin substituents on the midpoint potential in protein maquettes is analyzed.  This work details a full mechanism for, designing both an oxidoreductase and light harvesting protein, and how to control the redox chemistry.

Molecular assembly of proteins and cofactors for both oxidoreductases and light-harvesting proteins: A comprehensive mechanistic analysis

244th National Meeting (2012)

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