Comamonas testosteroni antA encodes an antimonite-translocating P-type ATPase

Area of Science:

• Environmental Science
• Microbiology
• Biochemistry

Background:

• Antimony (Sb) is an environmental metalloid with known toxicity, similar to arsenic.
• Microbial detoxification mechanisms for antimony are an emerging area of research.
• Understanding bacterial resistance to metalloids is crucial for environmental remediation.

Purpose of the Study:

• To identify and characterize novel bacterial mechanisms for antimony detoxification.
• To investigate the role of specific genes and proteins in conferring antimony resistance.
• To elucidate the function of a newly identified antimonite-translocating ATPase.

Main Methods:

• Comparative proteomics analysis of *Comamonas testosterone* JL40 under antimony stress.
• Gene expression analysis of the identified 'ant operon'.
• Heterologous expression of the *antA* gene in *E. coli* and functional characterization using everted membrane vesicles.

Main Results:

• A novel P_1B-type antimonite (Sb(III))-translocating ATPase (AntA) was identified in *Comamonas testosterone* JL40.
• The *ant* operon, including *antR*, *antC*, and *antA*, was upregulated by Sb(III).
• Expression of AntA conferred Sb(III) resistance and reduced intracellular Sb(III) in *E. coli*, with AntC potentially acting as an Sb(III) chaperone.

Conclusions:

• A novel Sb(III)-translocating ATPase (AntA) and its associated regulatory and chaperone proteins (AntR, AntC) confer bacterial resistance to antimony.
• This discovery expands the known repertoire of metalloid detoxification systems.
• The findings contribute to understanding the biogeochemical cycling of antimony in the environment.