Complete genome sequence of Comamonas testosteroni TA441 and comparative analysis of steroid degradation gene clusters across Proteobacteria and Actinomycetota
Year: 2026
Type: preprint
Abstract: ABSTRACT Comamonas testosteroni TA441 is a model aerobic steroid-degrading bacterium whose sterane degradation pathway has been elucidated in greater detail than that of any other bacterium to date. Similar pathways have been identified in many bacterial genera, including members of Proteobacteria and Actinomycetota, such as Mycobacterium tuberculosis . Steroid degradation genes in TA441 form an approximately 120-kb mega-cluster, and 40 genes involved mainly in the degradation of the sterane structure and the C20–C22 portion of the side chain at C17 have been identified. Here, we present the complete genome sequence of TA441 together with our findings on its steroid degradation genes. We also compare the genes in the mega-cluster with corresponding genes in other Comamonas strains, β-Proteobacteria other than Comamonas , γ-Proteobacteria, α-Proteobacteria, and Actinomycetota using CAGECAT to analyze similarities and differences in steroid degradation genes among these bacteria. IMPORTANCE Comamonas testosteroni TA441 is a key model organism for studying bacterial aerobic steroid degradation, and its pathways for cleavage of the A-, B-, C-, and D-rings have been extensively studied. These pathways and their enzymes show striking similarities among bacteria, including Mycobacterium tuberculosis , in which cholesterol degradation contributes to persistence in chronically infected lungs. However, the ecological and physiological significance of bacterial steroid degradation remains incompletely understood. Although TA441 is one of the best-studied steroid-degrading bacteria, its complete genome sequence had not been determined. In addition, TA441 and Comamonas thiooxydans CNB-2 have sometimes been described as nearly identical strains, although CNB-2 has not been studied for steroid degradation since its genome was published in 2009. Here, we present the complete genome sequence of TA441 and a detailed, gene-by-gene comparison of its steroid degradation genes with those of other bacteria, including M. tuberculosis . This study provides a foundation for understanding the diversity and potential ecological and physiological significance of bacterial steroid degradation.
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
Funder: RIKEN
OpenAlex ID: W7213965623