Discovered by genomics: putative reductive dehalogenases with N-terminus transmembrane helixes

Area of Science:

• Microbiology
• Biochemistry
• Environmental Science

Background:

• Organohalogen bioremediation relies on organohalide-respiring bacteria possessing reductive dehalogenase (RDase) enzymes.
• RDases typically comprise a catalytic subunit (RdhA) and a membrane anchor (RdhB).
• Genomic studies revealed a novel RDase gene lacking an rdhB gene but featuring N-terminal transmembrane helices.

Purpose of the Study:

• To investigate the nature and prevalence of a putative hybrid RDase.
• To explore the potential functionality and phylogenetic placement of these novel RDases.

Main Methods:

• Bioinformatic analysis of (meta)genomic data.
• Phylogenetic analysis of putative RDase sequences.
• Analysis of predicted protein localization.

Main Results:

• Hybrid putative RDase genes were identified in Deltaproteobacteria, Bacteroidetes, and candidate divisions.
• These hybrid RDases likely integrate directly into the membrane via N-terminal transmembrane helices.
• Phylogenetic analysis shows these novel RDases cluster separately from known groups.

Conclusions:

• A novel class of hybrid RDases, directly membrane-associated, has been identified across diverse bacterial phyla.
• The functionality and ecological significance of these hybrid RDases warrant further investigation.
• Expanding genomic data will likely reveal more diverse and novel RDase enzymes.