Experimental and Computational Evaluation of Nicotinamide Cofactor Biomimetics

Area of Science:

• Biocatalysis and enzyme engineering
• Synthetic chemistry and biomimetic design

Background:

• Oxidoreductase enzymes are valuable biocatalysts requiring nicotinamide cofactors (NAD(P)H).
• Synthetic nicotinamide cofactor biomimetics (NCBs) aim to overcome limitations of natural cofactors, offering tunable properties.
• Understanding structure-activity relationships (SARs) is crucial for rational NCB design and innovation.

Purpose of the Study:

• To systematically investigate the impact of linker length and aryl ring substitution on NCB performance.
• To elucidate the underlying mechanisms governing NCB stability, redox potential, and catalytic activity.
• To establish design principles for creating improved NCBs with customized properties.

Main Methods:

• Synthesis and characterization of novel NCB analogues with varying linker lengths and Ring 2 substituents.
• Electrochemical analysis to determine redox potentials and stability.
• Enzymatic catalysis assays using oxidoreductases to evaluate NCB activity and enzyme compatibility.
• Computational modeling, including Density Functional Theory (DFT), to understand SARs and reaction mechanisms.

Main Results:

• Linker length significantly impacts redox activity, with two- and three-carbon linkers showing optimal performance.
• Electron-donating substituents on the unconjugated aryl group (Ring 2) substantially enhance reductive potential.
• Enzyme-dependent tolerance and sensitivity to NCB structures were observed during catalytic transformations.
• Computational studies revealed stabilizing interactions (π-π stacking, charge transfer) between Ring 2 and the nicotinamide moiety.

Conclusions:

• Systematic SAR studies provide critical insights into NCB design for enhanced biocatalysis.
• Tailoring linker length and Ring 2 substituents allows for fine-tuning of NCB redox properties.
• The findings facilitate the rational design of next-generation NCBs for diverse enzymatic applications.