Dataset Information

Ring A cleaving beta-diketon hydrolase is a key enzyme of steroid degradation in anaerobic bacteria

ABSTRACT: Bacterial degradation of the ubiquitous and persistent steroids is important for their removal from the environment, particularly for the endocrine disrupting steroid sex hormones. While aerobic bacteria use oxygenases to attack non-activated C-H/C-C bonds of the isoprenoid side chain or the steran skeleton of steroids, initial studies of steroid degradation in anaerobic bacteria suggested that water-dependent enzymes are involved in C-H hydroxylation and ring cleavage reactions. In anaerobic steroid catabolism, the hydrolytic enzymes involved in the cleavage of the steran ring system of the common intermediate androst-1,4-diene-3-one have remained unknown. Here, we have enriched a hydrolase from the cholesterol/nitrate grown Sterolibacterium denitrificans and from Escherichia coli after heterologous expression of its gene. It specifically cleaves the cyclic 1,3-diketone degradation intermediate of ring A, androsta-1,4,17-trione, to 1,17-dioxo-2,3-seco-androstan-3-oate (DSAO), a hallmark reaction of anaerobic steroid degradation. The highly conserved ring A hydrolase was identified in all known and many previously unknown steroid-degrading Proteobacteria. Using the enriched enzyme, we enzymatically produced the CoA ester of DSAO from the chemically synthesized androst-1-ene-3-one precursor, allowing the identification of subsequent metabolites involved in ring A degradation. The results obtained suggest the involvement of an additional hydrolase, an aldolase, and a -oxidation-like cascade for complete ring A degradation during which acetate and acetyl-CoA are released to form the three-ring 5,10-seco-1,2,3,4-tetranorandrosta-5,17-dione. The results identified a key enzyme of anaerobic steroid degradation that may serve as functional marker for monitoring steroid contaminant degradation at anoxic environmental sites.

INSTRUMENT(S): Synapt MS

ORGANISM(S): Sterolibacterium Denitrificans

SUBMITTER: Lina Peller

LAB HEAD: Matthias Boll

PROVIDER: PXD053345 | Pride | 2025-05-07

REPOSITORIES: Pride

ACCESS DATA

Dataset's files

Source:

			Action	DRS
	20230623_LA_MO_24.raw.zip	Raw
	20230623_LA_MO_24_IA_final_fragment.csv	Csv
	20230623_LA_MO_24_IA_final_peptide.csv	Csv
	20230623_LA_MO_24_IA_final_protein.csv	Csv
	20230623_LA_MO_28.raw.zip	Raw

Items per page:

1 - 5 of 8

Publications

Ring A Cleaving Beta-Diketone Hydrolase Is a Key Enzyme of Steroid Degradation in Anaerobic Bacteria.

Jacoby Christian C Peller Lina L Wenzler Jana J Luttermann Monika M Seiche Wolfgang W Breit Bernhard B Boll Matthias M

Environmental microbiology 20250101 1

Bacterial degradation of ubiquitous and persistent steroids such as steroid hormones is important for their removal from the environment. Initial studies of steroid degradation in anaerobic bacteria suggested that ring-cleaving hydrolases are involved in oxygen-independent sterane skeleton degradation. However, the enzymes involved in ring A cleavage of the common intermediate androsta-1,4-diene-3,17-dione have remained unknown. Here, we enriched a ring A hydrolase from cholesterol/nitrate grown ...[more]

PMID: 39868648

Similar Datasets

Project description:Rhodococcus jostii RHA1 is a catabolically versatile soil actinomycete that can utilize a wide range of organic compounds as growth substrates including steroids. To globally assess the adaptation of the protein composition in the membrane fraction to steroids, the membrane proteomes of RHA1 grown on each of cholesterol and cholate were compared to pyruvate-grown cells using gel-free SIMPLE-MudPIT technology. Label-free quantification by spectral counting revealed 59 significantly regulated proteins, many of them present only during growth on steroids. Cholesterol and cholate induced distinct sets of steroid-degrading enzymes encoded by paralogous gene clusters, consistent with transcriptomic studies. CamM and CamABCD, two systems that take up cholate metabolites, were found exclusively in cholate-grown cells. Similarly, 9 of the 10 Mce4 proteins of the cholesterol uptake system were found uniquely in cholesterol-grown cells. Bioinformatic tools were used to construct a model of Mce4 transporter within the RHA1 cell envelope. Finally, comparison of the membrane and cytoplasm proteomes indicated that several steroid-degrading enzymes are membrane-associated. The implications for the degradation of steroids by actinomycetes, including cholesterol by the pathogen Mycobacterium tuberculosis , are discussed. Bioinformatics and data processing: All database searches were performed using SEQUEST algorithm, embedded in BioworksTM (Rev. 3.3.1, Thermo Fisher Scientific Inc., Waltham, MA), with a RHA1 database containing 9145 sequences. Only tryptic peptides with up to two missed cleavages were accepted. No fixed modifications were considered. Oxidation of methionine was permitted as variable modification. The mass tolerance for precursor ions was set to 10 ppm; the mass tolerance for fragment ions was set to 1 amu. For protein identification a threshold for deltaCn (0.08) and for XCorr values was defined, depending on the peptide charge (>2.5 (+2); > 3.5 (+3)). A protein was considered identified if at least two different peptides met these criteria. To assess the false discovery rate (FDR) of protein identification, a database with reversed protein sequences was searched retaining the search parameters and filter criteria. The FDR was calculated by dividing the absolute number of hits from the reversed database through the sum of hits from both database searches (reversed database and original database). Using the stringent criteria described above, no reversed database hit was found; therefore, the FDR was 0% in all measurements. This low error rate can be attributed to the additional demand for two different peptide matches per protein, which eliminated all otherwise observed protein hits against the decoy database.

Project description:Commensal microbes are exposed to enterohepatically circulated steroids such as bile acids and hormones in the gastrointestinal, vaginal, and urinary tracts. Since commensal microbes are exposed to these molecules exclusively in association with their host, we hypothesized that they may serve as effectors to identify and characterize genetic pathways involved in the commensal-host relationship. Host specific and some ingested steroids (phytoestrogens) are enterohepatically circulated through the lumen of the small intestine. Bile acid steroids are present at high concentrations, approximating 4 to 20 mM in the duodenum, and are released in bile from the common bile duct. Steroid hormones are secreted in bile at levels approximating 6 to 13 mg per day once conjugated to glucuronide or sulfate by the liver. Re-absorption of steroids by the terminal ileum is an incomplete process: for example, 200 to 600 mg of bile acid steroids per day in humans escape to the colon where complex microbial populations exist. We have shown that steroid hormones estradiol, progesterone, and hydrocortisone serve as strong substrates for the major RND- and MFS-type (except hydrocortisone) tripartite multidrug efflux systems, AcrAB-TolC and EmrAB-TolC respectively, even though such molecules fail to demonstrate antimicrobial properties in this bacterial background (Elkins and Mullis [2006] J. Bacteriol. 188:1191-1195). Although bile acids are subject to efflux, they are also known to directly interact with intracellular global regulators such as MarR (Prouty et al. [2004] Microbiol. 150:775-783) and Rob (Rosenberg et al., [2003] Mol. Microbiol. 48:1609-1619) consequently altering antimicrobial and bile resistance profiles. In our present study, whole-genome DNA microarrays of E. coli were used to determine what general effect steroids, both bile acid and hormones, may have on the transcriptome in relation to the human commensal environment. Keywords: Comparative Chemical Class Treatment

Project description:Anaerobic benzene oxidation coupled to the reduction of Fe(III) was studied in Ferroglobus placidus in order to learn more about how such a stable molecule could be metabolized under strict anaerobic conditions. F. placidus conserved energy to support growth at 85°C in a medium with benzene provided as the sole electron donor and Fe(III) as the sole electron acceptor. The stoichiometry of benzene loss and Fe(III) reduction, as well as the conversion of [14C]-benzene to [14C]-carbon dioxide, was consistent with complete oxidation of benzene to carbon dioxide with electron transfer to Fe(III). Benzoate, but not phenol or toluene, accumulated at low levels during benzene metabolism and [14C]-benzoate was produced from [14C]-benzene. Analysis of gene transcript levels revealed increased expression of genes encoding enzymes for anaerobic benzoate degradation during growth on benzene versus growth on acetate, but genes involved in phenol degradation were not up-regulated during growth on benzene. A gene for a putative carboxylase that was more highly expressed in benzene- versus benzoate-grown cells was identified. These results suggest that benzene is carboxylated to benzoate and that phenol is not an important intermediate in the benzene metabolism of F. placidus. This is the first demonstration of a microorganism in pure culture that can grow on benzene under strict anaerobic conditions and for which there is strong evidence for degradation of benzene via clearly defined anaerobic metabolic pathways. Thus, F. placidus provides a much needed pure culture model for further studies on the anaerobic activation of benzene in microorganisms. A five-chip study using total RNA recovered from three separate cultures of Ferroglobus placidus DSM 10642 grown with 0.5 mM phenol (experimental condition) and two separate cultures of Ferroglobus placidus DSM 10642 grown on 1 mM benzoate (control condition). Each chip measures the expression level of 2,613 genes from Ferroglobus placidus DSM 10642 with nine 45-60-mer probe pairs (PM/MM) per gene, with three-fold technical redundancy.