Steroid degradation genes in Comamonas testosteroni TA441: Isolation of genes encoding a Δ4(5)-isomerase and 3α- and 3β-dehydrogenases and evidence for a 100kb steroid degradation gene hot spot

Horinouchi, Masae; Kurita, Tomokazu; Hayashi, Toshiaki; Kudo, Toshiaki

doi:10.1016/j.jsbmb.2010.06.002

Cited by 60 publications

(62 citation statements)

References 74 publications

(90 reference statements)

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“…A possible terminator was found just downstream of the putative 317-hsd gene and the homology search indicated that a protein encoded by a putative ORF in the downstream DNA region (ORF63, Figure 3.) to be a secretion lowering protein 1, suggesting that the DNA region downstream of the 317-hsd are not involved in steroid degradation [37].…”

Section: -1 3-17-dehydrogenationmentioning

confidence: 99%

“…A gene-disrupted mutant of 3,17-hsd of strain TA441 did not show significant growth on epiandrosterone, which has a 3-hydroxyl group and 17-ketone group, while the gene-disrupted mutant did degrade testosterone, which has a 17-hydroxyl group and 3-ketone group, though the growth was noticeably slower than that of the strain TA441 control [accepted, Horinouchi 2010]. These results suggested that the main role of the 3,17-hsd in TA441 cells is 3-dehydrogenation and that there is at least one more dehydrogenase which acts on the 17-hydroxyl group.…”

Section: -1 3-17-dehydrogenationmentioning

confidence: 99%

“…A ∆5,3-ketosteroid isomerase-disrupted mutant of strain TA441 can grow on dehydroepiandrosterone, which has a double bond at ∆5, but cannot grow on epiandrosterone, which lacks a double bond at ∆5, indicating that C. testosteroni ksi is responsible for transfer of the double bond from ∆5 to ∆4 and transfer of the double bond by hydrogenation at ∆5 and following dehydrogenation at ∆4 is not possible [37].…”

Section: -3 ∆53-ketosteroid Isomerationmentioning

confidence: 99%

“…testosteroni is unable to degrade majority of the steroid compounds with a large side chain at C-17 position such as cholesterols and plant sterols [37], but effectively degrades cholic acid and the derivatives. Cholic acid and the derivatives are not only known for physiological activities on animals and anti-bacterial activity as the main integrants of bile acid [50][51][52][53][54][55][56][57][58][59] but also other various functions that are expected to be applied to medicals and their materials.…”

Section: -4 Degradation Of the Side Chain At C-17 Position Of Cholimentioning

confidence: 99%

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Steroid degradation in Comamonas testosteroni

Horinouchi

Hayashi

Kudo

2012

The Journal of Steroid Biochemistry and Molecular Biology

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114

153

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Steroid degradation by Comamonas testosteroni and Nocardia restrictus have been intensively studied for the purpose of obtaining materials for steroid drug synthesis. C. testosteroni degrades side chains and converts single/double bonds of certain steroid compounds to produce androsta-1,4-diene 3,17-dione or the derivative. Following 9-hydroxylation leads to aromatization of the A-ring accompanied by cleavage of the B-ring, and aromatized A-ring is hydroxylated at C-4 position, cleaved at ∆4 by meta-cleavage, and divided into 2-hydroxyhexa-2,4-dienoic acid (A-ring) and 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid (B,C,D-ring) by hydrolysis.Reactions and the genes involved in the cleavage and the following degradation of the A-ring are similar to those for bacterial biphenyl degradation, and 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid degradation is suggested to be mainly -oxidation. Genes involved in A-ring aromatization and degradation form a gene cluster, and the genes involved in -oxidation of 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid also comprise a large cluster of more than 10 genes. The DNA region between these two main steroid degradation gene clusters contain 3-hydroxysteroid dehydrogenase gene, ∆5,3-ketosteroid isomerase gene, genes for inversion of an -oriented-hydroxyl group to a -oriented-hydroxyl group at C-12 position of cholic acid, and genes possibly involved in the degradation of a side chain at C-17 position of cholic acid, indicating this DNA region of more than 100kb to be a steroid degradation gene hot spot of C. testosteroni.

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Section: -1 3-17-dehydrogenationmentioning

confidence: 99%

Section: -1 3-17-dehydrogenationmentioning

confidence: 99%

Section: -3 ∆53-ketosteroid Isomerationmentioning

confidence: 99%

Section: -4 Degradation Of the Side Chain At C-17 Position Of Cholimentioning

confidence: 99%

See 2 more Smart Citations

Steroid degradation in Comamonas testosteroni

Horinouchi

Hayashi

Kudo

2012

The Journal of Steroid Biochemistry and Molecular Biology

Self Cite

114

153

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“…strain Chol1. In the former strain, genes responsible for oxidation of the steroid nucleus were found (10)(11)(12)(13), while in the latter, genes responsible for degradation of the cholate side chain were identified, including acad, encoding an acyl coenzyme A (acyl-CoA) dehydrogenase (2), and skt, encoding a thiolase (3).…”

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confidence: 99%

Gene Cluster Encoding Cholate Catabolism in Rhodococcus spp

et al. 2012

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bBile acids are highly abundant steroids with important functions in vertebrate digestion. Their catabolism by bacteria is an important component of the carbon cycle, contributes to gut ecology, and has potential commercial applications. We found that Rhodococcus jostii RHA1 grows well on cholate, as well as on its conjugates, taurocholate and glycocholate. The transcriptome of RHA1 growing on cholate revealed 39 genes upregulated on cholate, occurring in a single gene cluster. Reverse transcriptase quantitative PCR confirmed that selected genes in the cluster were upregulated 10-fold on cholate versus on cholesterol. One of these genes, kshA3, encoding a putative 3-ketosteroid-9␣-hydroxylase, was deleted and found essential for growth on cholate. Two coenzyme A (CoA) synthetases encoded in the cluster, CasG and CasI, were heterologously expressed. CasG was shown to transform cholate to cholyl-CoA, thus initiating side chain degradation. CasI was shown to form CoA derivatives of steroids with isopropanoyl side chains, likely occurring as degradation intermediates. Orthologous gene clusters were identified in all available Rhodococcus genomes, as well as that of Thermomonospora curvata. Moreover, Rhodococcus equi 103S, Rhodococcus ruber Chol-4 and Rhodococcus erythropolis SQ1 each grew on cholate. In contrast, several mycolic acid bacteria lacking the gene cluster were unable to grow on cholate. Our results demonstrate that the above-mentioned gene cluster encodes cholate catabolism and is distinct from a more widely occurring gene cluster encoding cholesterol catabolism. Bile salts are surface-active steroids with an important role in the uptake and metabolism of lipophilic substrates in vertebrates. These steroids, which include cholate and chenodeoxycholate, are synthesized in the liver from cholesterol, and their eventual fate is excretion in feces or urine. Bile salts may be modified, either by microbiological activity in the duodenum or by host cell bioactivity, leading to their conjugation to glycine, taurine, or sulfate. As such, biodegradation of the various bile salts is a significant process in carbon cycling in soil and aquatic environments. The processes involved in microbial transformation of steroids are also relevant for biotechnological applications in the synthesis and/or selective modification of steroid-based drugs (29).Despite the cytotoxicity of cholate toward various prokaryotic and eukaryotic cells, several bacterial species, especially members of the Proteobacteria (27, 28) and Actinomycetales (9, 32), are able to efficiently metabolize this substrate to sustain growth. Recent studies on microbial bile salts degradation have focused on the Proteobacteria. Genes encoding several steps in cholate degradation were identified, mainly in Comamonas testosteroni TA441 and Pseudomonas sp. strain Chol1. In the former strain, genes responsible for oxidation of the steroid nucleus were found (10-13), while in the latter, genes responsible for degradation of the cholate side chain were identified, in...

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