Characterizing Y224 conformational flexibility in FtmOx1-catalysis using ¹⁹F NMR spectroscopy

Area of Science:

• Biochemistry
• Enzymology
• Natural Product Biosynthesis

Background:

• α-Ketoglutarate-dependent non-haem iron (αKG-NHFe) enzymes are vital in natural product synthesis.
• Some αKG-NHFe enzymes exhibit multifunctional catalytic capabilities.
• FtmOx1 is an αKG-NHFe enzyme involved in verruculogen biosynthesis, catalyzing multiple reactions.

Purpose of the Study:

• To investigate the role of active site tyrosine (Y224) conformational dynamics in FtmOx1's multifunctional catalysis.
• To elucidate the mechanism by which specific enzyme-substrate conformations affect catalytic activities.

Main Methods:

• Site-directed mutagenesis using amber codon suppression to create a Y224-to-3,5-difluorotyrosine mutant.
• ¹⁹F NMR spectroscopy to assess enzyme structural flexibility.
• Biochemical assays and X-ray crystallography to analyze enzyme-substrate complexes and catalytic outcomes.

Main Results:

• The Y224 substitution provided insights into FtmOx1's structural flexibility via ¹⁹F NMR.
• Biochemical and crystallographic data revealed correlations between FtmOx1 conformations and substrate-specific catalytic activities.
• The study demonstrates the utility of ¹⁹F NMR for studying enzyme dynamics.

Conclusions:

• Conformational dynamics of active site residues, like Y224, are critical for the multifunctional catalysis of FtmOx1.
• Understanding these dynamics can guide the engineering of novel biocatalysts.
• ¹⁹F NMR is a valuable tool for mechanistic studies of complex enzymes.