A designed heme-[4Fe-4S] metalloenzyme catalyzes sulfite reduction like the native enzyme

Abstract

Multielectron redox reactions often require multicofactor metalloenzymes to facilitate coupled electron and proton movement, but it is challenging to design artificial enzymes to catalyze these important reactions, owing to their structural and functional complexity. We report a designed heteronuclear heme-[4Fe-4S] cofactor in cytochrome peroxidase as a structural and functional model of the enzyme sulfite reductase. The initial model exhibits spectroscopic and ligand-binding properties of the native enzyme, and sulfite reduction activity was improved-through rational tuning of the secondary sphere interactions around the [4Fe-4S] and the substrate-binding sites-to be close to that of the native enzyme. By offering insight into the requirements for a demanding six-electron, seven-proton reaction that has so far eluded synthetic catalysts, this study provides strategies for designing highly functional multicofactor artificial enzymes.

Mimochrome, a metalloporphyrin‐based catalytic Swiss knife†

“…These putative Cu B and Fe B sites, together with heme, were not only structural and functional mimetics but were helpful in elucidating key aspects about the activity of their natural counterparts [126][127][128]. More recently, cytochrome c peroxidase (CcP) activity was steered toward an active SiR surrogate by installing a [4Fe-4S] cofactor in its proximal site [129]. Huge amount of research has been done on P450s engineering and repurposing.…”

Enhancement of protein stability by an additional disulfide bond designed in human neuroglobin

“…[1][2][3][4][5][6] In order to expand their functionalities, researchers have made great efforts in the design of articial metalloproteins and metalloenzymes. 1,[7][8][9][10][11][12][13][14][15][16][17] Since enzyme activity is affected by many factors, increasing the protein stability may ensure the articial enzymes to be active under harsh reaction conditions, such as in presence of denaturing agents, with high temperature and in different pH solutions. For this purpose, various strategies have been developed in the last decade, such as rational design, 18 directed evolution, 19 and computational design, 20 by improving the hydrophobic and hydrogen(H)bonding interactions within the protein scaffold.…”

Design of a Fe4S4 cluster into the core of a de novo four‐helix bundle

“…The resulting protein-DJB1-is related to previous designs [36,37], where the metal coordination environment was designed to match the preexisting geometry of the protein scaffold. However, DJB1 differs from both previous designs [47][48][49][50][51][52] and all known natural iron-sulfur proteins in that the four metal-binding cysteines are well separated in the primary sequence, with each located on a different α-helix. The four ligand positions were chosen by computationally probing all residue combinations and identifying energetically and geometrically feasible solutions [53].…”