4TPO

High-resolution structure of TxtE with bound tryptophan substrate

Summary for 4TPO

• Entry DOI: 10.2210/pdb4tpo/pdb
• Related: 4TPN
• Descriptor: Putative P450-like protein, PROTOPORPHYRIN IX CONTAINING FE, GLYCEROL, ... (6 entities in total)
• Functional Keywords: cytochrome, p450, heme, nitration, oxidoreductase
• Biological source: Streptomyces scabies
• Total number of polymer chains: 1
• Total formula weight: 46452.32

Authors

Cahn, J.K.B.,Dodani, S.C.,Brinkmann-Chen, S.,Heinsich, T.,McIntosh, J.A.,Arnold, F.H. (deposition date: 2014-06-08, release date: 2014-09-10, Last modification date: 2023-12-27)

Primary citation

Dodani, S.C.,Cahn, J.K.,Heinisch, T.,Brinkmann-Chen, S.,McIntosh, J.A.,Arnold, F.H.
Structural, Functional, and Spectroscopic Characterization of the Substrate Scope of the Novel Nitrating Cytochrome P450 TxtE.
Chembiochem, 15:2259-2267, 2014

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.

PubMed: 25182183
DOI: 10.1002/cbic.201402241

Experimental method

X-RAY DIFFRACTION (1.225 Å)