Download MendeleyStructural, Functional, and Spectroscopic Characterization of the Substrate Scope of the Novel Nitrating Cytochrome P450 TxtE.
Dodani, S.C., Cahn, J.K., Heinisch, T., Brinkmann-Chen, S., McIntosh, J.A., Arnold, F.H.(2014) Chembiochem 15: 2259-2267
- PubMed: 25182183
- DOI: https://doi.org/10.1002/cbic.201402241
- Primary Citation of Related Structures:
4TPN, 4TPO - PubMed Abstract:
A novel cytochrome P450 enzyme, TxtE, was recently shown to catalyze the direct aromatic nitration of L-tryptophan. This unique chemistry inspired us to ask whether TxtE could serve as a platform for engineering new nitration biocatalysts to replace current harsh synthetic methods. As a first step toward this goal, and to better understand the wild-type enzyme, we obtained high-resolution structures of TxtE in its substrate-free and substrate-bound forms. We also screened a library of substrate analogues for spectroscopic indicators of binding and for production of nitrated products. From these results, we found that the wild-type enzyme accepts moderate decoration of the indole ring, but the amino acid moiety is crucial for binding and correct positioning of the substrate and therefore less amenable to modification. A nitrogen atom is essential for catalysis, and a carbonyl must be present to recruit the αB'1 helix of the protein to seal the binding pocket.
Organizational Affiliation:
Division of Chemistry and Chemical Engineering, California Institute of Technology, MC 210-41 Pasadena, CA (USA).
