4z43
From Proteopedia
Crystal structure of Tryptophan 7-halogenase (PrnA) Mutant E450K
Structural highlights
Function[PRNA_PSEFL] Involved in the biosynthesis of the antifungal antibiotic pyrrolnitrin. Catalyze the chlorination of tryptophan (Trp) at C7 position to yield 7-chloro-L-tryptophan (7-CLT). The reaction between FADH2, Cl-, and O2 generates the powerful oxidant HOCl, which is presumed to carry out the chlorination reaction. The reaction of HOCl with the active site Lys-79 generates a lysine chloramine, which plays a key role in directing regiospecific chlorination of substrate in this important class of biosynthetic enzymes. It is also able to use bromide ions to generate monobrominated Trp.[1] [2] [3] Publication Abstract from PubMedFlavin-dependent halogenases are potentially valuable biocatalysts for the regioselective halogenation of aromatic compounds. These enzymes, utilising benign inorganic halides, offer potential advantages over traditional non-enzymatic halogenation chemistry that often lacks regiocontrol and requires deleterious reagents. Here we extend the biocatalytic repertoire of the tryptophan halogenases, demonstrating how these enzymes can halogenate a range of alternative aryl substrates. Using structure guided mutagenesis we also show that it is possible to alter the regioselectivity as well as increase the activity of the halogenases with non-native substrates including anthranilic acid; an important intermediate in the synthesis and biosynthesis of pharmaceuticals and other valuable products. Extending the biocatalytic scope of regiocomplementary flavin-dependent halogenase enzymes.,Shepherd SA, Karthikeyan C, Latham J, Struck AW, Thompson ML, Menon BRK, Styles MQ, Levy C, Leys D, Micklefield J Chem Sci. 2015 Jun 1;6(6):3454-3460. doi: 10.1039/c5sc00913h. Epub 2015 Apr 10. PMID:29511510[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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