Predicting the Substrate Scope of the Flavin-Dependent Halogenase BrvH.

Area of Science:

• Biochemistry
• Enzymology
• Structural Biology

Background:

• The flavin-dependent halogenase BrvH exhibits both bromination and chlorination activity on indole, with a preference for bromination.
• Despite annotation as a tryptophan halogenase, BrvH does not accept tryptophan as a substrate, leaving its native substrate unidentified.

Purpose of the Study:

• To develop a predictive model for BrvH activity based on its known substrate specificities.
• To identify potential novel substrates for BrvH through in silico screening.
• To explore the enzyme's role in natural product biosynthesis.

Main Methods:

• Construction of a complete protein model of BrvH using X-ray structure and molecular mechanics.
• In vitro docking of known substrates and non-substrates into the BrvH active site.
• Analysis of atomic parameters (distance, partial charge, hybridization) to establish activity prediction rules.
• Virtual screening of compound libraries and a natural product database using the developed predictive model.

Main Results:

• A predictive model for BrvH activity was successfully developed.
• Virtual screening identified several potential substrates, which were subsequently validated in vitro.
• Screening of a natural product database yielded additional potential substrates/products.

Conclusions:

• The developed predictive model accurately identifies BrvH substrates.
• The study successfully identified novel substrates for BrvH, expanding the known substrate scope.
• This work provides a foundation for further investigating BrvH's biological role and potential applications in natural product discovery.