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Metagenomic Analysis of Silage
Published on: January 13, 2017
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A flavin-dependent halogenase from metagenomic analysis prefers bromination over chlorination
Pia R Neubauer1, Christiane Widmann2, Daniel Wibberg3
1Organic and Bioorganic Chemistry (OCIII), Bielefeld University, Bielefeld, Germany.
Plos One
|May 11, 2018
Summary
Researchers discovered novel marine flavin-dependent halogenases using a Hidden-Markov-Model. One enzyme, brvH, actively converts indole to 3-bromoindole, even with high chloride concentrations, offering new biocatalysis potential.
Area of Science:
- Biochemistry
- Marine Biology
- Enzymology
Background:
- Flavin-dependent halogenases are crucial enzymes for aromatic compound halogenation.
- Marine environments are rich in halides, suggesting potential for novel halogenase discovery.
- Existing methods for identifying halogenases may not fully capture marine biodiversity.
Purpose of the Study:
- To identify novel flavin-dependent halogenases from marine metagenomes.
- To characterize the activity and structure of a newly discovered marine halogenase.
- To explore the potential of marine organisms as sources of unique biocatalysts.
Main Methods:
- Utilized a Hidden-Markov-Model (HMM) based on the PFAM tryptophan halogenase model.
- Screened eleven marine metagenomes for putative halogenase genes.
- Selected, codon-optimized, and overexpressed the brvH gene in E. coli.
- Performed substrate screening and determined the crystal structure of the BrvH enzyme.
Main Results:
- Identified 254 complete or partial putative flavin-dependent halogenase genes in marine metagenomes.
- The overexpressed BrvH enzyme demonstrated active flavin-dependent halogenase activity, converting indole to 3-bromoindole.
- Bromination by BrvH occurred efficiently even in the presence of excess chloride ions.
- The crystal structure of BrvH revealed a unique open substrate binding site compared to known tryptophan halogenases.
Conclusions:
- Marine metagenomes harbor a significant number of novel flavin-dependent halogenase genes.
- BrvH is a novel, active marine flavin-dependent halogenase with potential for biocatalytic applications.
- The unique structural features of BrvH may explain its substrate specificity and activity in high-halide environments.
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