SEARCH · PubMed Health

Results for “Comamonas”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources

PubMed2001

3alpha-Hydroxysteroid dehydrogenase/carbonyl reductase from Comamonas testosteroni: biological significance, three-dimensional structure and gene regulation.

3alpha-Hydroxysteroid dehydrogenase/carbonyl reductase (3alpha-HSD/CR) catalyses the oxidoreduction at carbon 3 of steroid hormones and is postulated to initiate the complete mineralisation of the steroid nucleus to CO(2) and H(2)O in Comamonas testosteroni. The enzyme was found to be functional towards a variety of steroid substrates, including the steroid antibiotic fusidic acid. The enzyme also catalyses the carbonyl reduction of non-steroidal aldehydes and ketones such as a novel insecticide. It is suggested that 3alpha-HSD/CR contributes to important defense strategies of C. testosteroni against natural and synthetic toxicants. The 3alpha-HSD/CR gene (hsdA) is 774 base pairs long and the deduced amino acid sequence comprises 258 residues with a calculated molecular mass of 26.4 kDa. A homology search revealed 3alpha-HSD/CR as a new member of the short-chain dehydrogenase/reductase (SDR) superfamily. Upon gel permeation chromatography the purified enzyme elutes as a 49.4 kDa protein indicating a dimeric nature of 3alpha-HSD/CR. The protein was crystallised and the structure solved by X-ray analysis. The crystal structure reveals one homodimer per asymmetric unit, thereby verifying its dimeric nature. Dimerisation takes place via an interface essentially built-up by helix alphaG and strand betaG of each subunit. So far, this type of intermolecular contact has exclusively been observed in homotetrameric SDRs, but never in the structure of a homodimeric SDR. The formation of a tetramer is blocked in 3alpha-HSD/CR by the presence of a predominantly alpha-helical subdomain, which is missing in all other SDRs of known structure. The promoter domain was localised within the 93 bp region upstream of hsdA and the transcriptional start site was identified at 28 bp upstream of the translation start site. Interestingly, hsdA expression was found to be under negative control by two repressor proteins, the genes of which were found in opposite direction downstream or overlapping with hsdA. Based on our results, we propose that induction of hsdA expression in C. testosteroni by steroids actually appears to be a de-repression by preventing the binding of repressor proteins to regulatory regions.

3-Hydroxysteroid Dehydrogenases↗

PubMed2001

A model on the regulation of 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase expression in Comamonas testosteroni.

3alpha-Hydroxysteroid dehydrogenase/carbonyl reductase (3alpha-HSD/CR) from Comamonas testosteroni is a key enzyme involved in the degradation of steroids and xenobiotic carbonyl compounds. The enzyme has recently been cloned and characterized by our group. A strong induction of enzyme activity is observed in the presence of steroids like testosterone. In the present investigation, two repressor proteins (Rep1 and Rep2) containing 78 and 420 amino acids, respectively, were found to regulate 3alpha-HSD/CR gene (hsdA) expression. Gel shift experiments showed that Rep2 binds to a 10 nucleotide sequence 9 bp upstream of the hsdA promoter. The deletion of this cis-regulating sequence significantly increases hsdA expression. About 1633 bp further upstream, a second ten nucleotide sequence, complementary to the first one, was found, which is also recognized by Rep2 and increases hsdA expression, if deleted. To purify the repressor proteins, the genes encoding each were cloned into His-tag expression vectors and overexpressed in Escherichia coli. Rep1 does not bind to DNA but may bind to 3alpha-HSD/CR mRNA as predicted by its secondary structure. Concluding from our data, induction of 3alpha-HSD/CR in C. testosteroni by steroids in fact appears to be a de-repression, where the steroidal 'inducer' prevents the binding of the two repressor proteins to the hsdA promoter and mRNA, respectively.

3-Hydroxysteroid Dehydrogenases↗

PubMed2003

Characterization and recombinant expression of the translational repressor RepB of 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase in Comamonas testosteroni.

3alpha-Hydroxysteroid dehydrogenase/carbonyl reductase (3alpha-HSD/CR) from Comamonas testosteroni is a key enzyme involved in the degradation of steroids and xenobiotic carbonyl compounds. The gene of 3alpha-HSD/CR (hsdA) was cloned and characterized by our group. We have also reported that two repressor proteins (RepA and RepB) have been identified which regulate hsdA expression. To further characterize RepB, the protein was expressed in Escherichia coli and purified in an active state. Gel shift experiments showed that RepB binds to a 16 nucleotide sequence downstream of AUG of the hsdA mRNA, providing evidence that RepB acts on the translational level. The addition of testosterone to the culture medium led to a derepression. Furthermore, a plasmid was prepared containing a point mutation that inactivates only repA, but has no effect on hsdA, with which it happens to partly overlap. The result of coexpression experiments with this construct and a plasmid containing the genetic information for RepB showed that RepB is still active and is therefore not dependent on a functional RepA. In conclusion, RepB is a novel regulatory protein that inhibits the translation of hsdA mRNA, thereby leading to a decreased expression of 3alpha-HSD/CR.

3-Hydroxysteroid Dehydrogenases↗

PubMed2004

Ability of bacterial biphenyl dioxygenases from Burkholderia sp. LB400 and Comamonas testosteroni B-356 to catalyse oxygenation of ortho-hydroxychlorobiphenyls formed from PCBs by plants.

Capacity of enzymes of the biphenyl/chlorobiphenyl pathway, especially biphenyl dioxygenase (BPDO) of two polychlorinated biphenyls (PCB) degrading bacteria, Burkholderia sp. LB400 and Comamonas testosteroni B-356, to metabolize ortho-substituted hydroxybiphenyls was tested.,These compounds found among plant products of PCB metabolism, are carrying chlorine atoms on the hydroxyl-substituted ring. The abilities of His-tagged purified LB400 and B-356 BPDOs to catalyze the oxygenation of 2-hydroxy-3-chlorobiphenyl, 2-hydroxy-5-chlorobiphenyl and 2-hydroxy-3,5-dichlorobiphenyl were compared. Both enzyme preparations catalyzed the hydroxylation of the three chloro-hydroxybiphenyls on the non-substituted ring. Neither LB400 BPDO nor B-356 BPDO oxygenated the substituted ring of the ortho-hydroxylated biphenyl. The fact that metabolites generated by both enzymes were identical for all three hydroxychlorobiphenyls tested; exclude any other mode of attack of these compounds by LB400 BPDOs than the ortho-meta oxygenation.

Biodegradation, Environmental↗

PubMed2000

Steroid-inducible transcription of the 3beta/17beta-hydroxysteroid dehydrogenase gene (3beta/17beta-hsd) in Comamonas testosteroni.

The expression of the Comamonas testosteroni gene, encoding 3beta/17beta-hydroxysteroid dehydrogenase enzyme (3beta/17beta-HSD), was analyzed at the transcriptional level. Northern blot analysis detected a 1 kb transcript in bacterial cells grown in minimum media supplemented with Casamino acids and testosterone. Also this transcript was observed when cells were grown in presence of 1-dehydrotestosterone, androstenedione and 1,4-androstadien-3, 17dione, but not in presence of acetate, citrate, cholic acid, cholesterol, and cortisol. In addition, this effect was dependent on the presence of another carbon source in the growth medium used, revealing catabolite repression.

17-Hydroxysteroid Dehydrogenases↗

PubMed2003

Chaperone-assisted expression, purification, and characterization of recombinant nitrile hydratase NI1 from Comamonas testosteroni.

Nitrile hydratases (NHases) are industrially important iron- and cobalt-containing enzymes that are used in the large-scale synthesis of acrylamide. Heterologous expression of NHases has been complicated by the fact that other proteins (activators or metallochaperones) appear to be required to produce NHases in their catalytically active form. We report a novel heterologous system for the expression of catalytically active iron-containing NI1 NHase in Escherichia coli, involving coexpression with the E. coli GroES and GroEL chaperones. The purified recombinant enzyme was found to be highly similar to the enzyme purified from Comamonas testosteroni according to its spectroscopic features, catalytic properties with various substrates, and post-translational modifications. In addition, we report a rapid and convenient spectrophotometric method to monitor the activity of NI1 NHase during purification.

Catalysis↗

PubMed2003

Deuterium isotope effect on enantioselectivity in the Comamonas testosteroni quinohemoprotein alcohol dehydrogenase-catalyzed kinetic resolution of rac-2,2-dimethyl-4-hydroxymethyl-1,3-dioxolane, solketal.

Isotopic substitution provides an effective tool to probe the mechanism of enzyme-catalyzed reactions. To our knowledge, kinetic isotope effects on the enantioselectivity of enzymes have not been reported. We investigated the effect of deuterium substitution on the enantiomeric ratio, E, of PQQ-containing quinohemoprotein alcohol dehydrogenase, QH-ADH, from Comamonas testosteroni in the ferricyanide-coupled kinetic resolution of rac-2,2-dimethyl-4-hydroxymethyl-1,3-dioxolane, solketal. Under otherwise identical conditions, we measured E=30 for solketal and E=6 for rac-2,2-dimethyl-4-[1,1-2H]hydroxymethyl-1,3-[5,5,4-2H]dioxolane, d(5)-solketal. It is proposed that isotopic substitution affects the relative kinetic weights of the initial hydron/deuteron transfer from substrate to cofactor and the subsequent proton/deuteron shift in the cofactor-product complex. The latter step becomes more important in the deuterated complex to the extent that the enantiomer discrimination in the first step is partially overruled.

Alcohol Oxidoreductases↗

PubMed2000

Equilibrium and kinetic analysis of folding of ketosteroid isomerase from Comamonas testosteroni.

Equilibrium and kinetic analyses have been carried out to elucidate the folding mechanism of homodimeric ketosteroid isomerase (KSI) from Comamonas testosteroni. The folding of KSI was reversible since the activity as well as the fluorescence and CD spectra was almost completely recovered after refolding. The equilibrium unfolding transitions monitored by fluorescence and CD measurements were almost coincident with each other, and the transition midpoint increased with increasing protein concentration. This suggests that the KSI folding follows a simple two-state mechanism consisting of native dimer and unfolded monomer without any thermodynamically stable intermediates. Sedimentation equilibrium analysis and size-exclusion chromatography of KSI at different urea concentrations supported the two-state model without any evidence of folded monomeric intermediates. Consistent with the two-state model, (1)H-(15)N HSQC spectra obtained for KSI in the unfolding transition region could be reproduced by a simple addition of the spectra of the native and the unfolded KSI. The KSI refolding kinetics as monitored by fluorescence intensity could be described as a fast first-order process followed by a second-order and a subsequent slow first-order processes with rate constants of 60 s(-)(1), 5.4 x 10(4) M(-)(1).s(-)(1), and 0.017 s(-)(1), respectively, at 0.62 M urea, suggesting that there may be a monomeric folding intermediate. After a burst phase that accounts for >83% of the total amplitude, the negative molar ellipticity at 225 nm increased slowly in a single phase at a rate comparable to that of the bimolecular intermediate step. The kinetics of activity recovery from the denatured state were markedly dependent upon the protein concentration, implying that the monomers are not fully active. Taken together, our results demonstrate that the dimerization induces KSI to fold into the complete structure and is crucial for maintaining the tertiary structure to perform efficient catalysis.

Chromatography, Gel↗

PubMed2001

Folding mechanism of ketosteroid isomerase from Comamonas testosteroni.

Ketosteroid isomerase (KSI) from Comamonas testosteroni is a homodimeric enzyme with 125 amino acids in each monomer catalyzing the allylic isomerization reaction at rates comparable to the diffusion limit. Kinetic analysis of KSI refolding has been carried out to understand its folding mechanism. The refolding process as monitored by fluorescence change revealed that the process consists of three steps with a unimolecular fast, a bimolecular intermediate, and most likely unimolecular slow phases. The fast refolding step might involve the formation of structured monomers with hydrophobic surfaces that seem to have a high binding capacity for the amphipathic dye 8-anilino-1-naphthalenesulfonate. During the refolding process, KSI also generated a state that can bind equilenin, a reaction intermediate analogue, at a very early stage. These observations suggest that the KSI folding might be driven by the formation of the apolar active-site cavity while exposing hydrophobic surfaces. Since the monomeric folding intermediate may contain more than 83% of the native secondary structures as revealed previously, it is nativelike taking on most of the properties of the native protein. Urea-dependence analysis of refolding revealed the existence of folding intermediates for both the intermediate and slow steps. These steps were accelerated by cyclophilin A, a prolyl isomerase, suggesting the involvement of a cis-trans isomerization as a rate-limiting step. Taken together, we suggest that KSI folds into a monomeric intermediate, which has nativelike secondary structure, an apolar active site, and exposed hydrophobic surface, followed by dimerization and prolyl isomerizations to complete the folding.

Aldose-Ketose Isomerases↗

PubMed2000

Active site residues of cis-2,3-dihydro-2,3-dihydroxybiphenyl dehydrogenase from Comamonas testosteroni strain B-356.

cis-2,3-dihydro-2,3-dihydroxybiphenyl dehydrogenase (BphB) from Comamonas testosteroni strain B-356 is the second enzyme of the biphenyl/polychlorinated biphenyl degradation pathway. Based on the crystal structure of a related BphB, three conserved residues, Ser142, Tyr155, and Lys159, have been suggested to function as a "catalytic triad" as for other members of the short-chain alcohol dehydrogenase/reductase (SDR) family. In this study, substitution of each triad residue was examined in BphB. At pH 9.0, turnover numbers relative to wild-type enzyme were as follows: Y155F, 0.1%; S142A, 1%; and K159A, 10%. Although the Michaelis constants of K159A and S142A for cis-2,3-dihydro-2,3-dihydroxybiphenyl increased about 20-fold, relatively little change was observed in the K(m) for dinucleotide. The K159A mutant, which showed little dehydrogenase activity at pH 7, was sharply activated by increasing the pH, reaching almost 25% of the activity of the wild-type enzyme at pH 9. 8. These three residues are therefore critical for BphB activity, as suggested by the crystal structure and similarity to other SDR family members. In addition, BphB showed a strong preference for NAD(+) over NADP(+), with a 260-fold higher specificity constant (k(cat)/K(m)). Evidence is presented that the inefficient use of NADP(+) by BphB might partly be due to the presence of an aspartate residue at position 36.

Amino Acid Sequence↗

PubMed2001

Potential application of catalase-peroxidase from Comamonas terrigena N3H in the biodegradation of phenolic compounds.

Comamonas terrigena N3H is a gram-negative rod-shaped bacterium that was isolated from contaminated soil in Slovakia. This bacterium showed remarkable biodegradation properties. We investigated the expression and functioning of two catalase isozymes in this bacterium. The typical catalase could be induced by cadmium ions, whereas the catalase-peroxidase enzyme was constitutively expressed. Since C. terrigena lacks the key enzyme for complete degradation of phenols (phenolhydroxylase), we analysed the possible removal of phenol by the two catalases of this bacterium. Addition of phenol to the culture medium led to increased expression of the catalase-peroxidase. Applying oxidative stress prior to phenol administration markedly induced the expression of the typical catalase, irrespective of the nature of the added agent. Thus, the rate of phenol degradation is rather reduced under these conditions, while growth of the cells is not impaired. We concluded that phenol peroxidation in C. terrigena can be largely attributed to the action of a catalase-peroxidase. The potential application of this enzyme in the removal of phenol from the environment is discussed.

Biodegradation, Environmental↗

PubMed2004

Lag period of 14CO2 evolution from dioctyl sulpho[2,3-14C]succinate in relation to adaptation of bacterium, Comamonas terrigena, to dialkyl esters of sulphosuccinate.

Comamonas terrigena, strain N3H, which was isolated from soil polluted with crude oil products, degraded dioctyl sulphosuccinate, a synthetic commercial surfactant. The primary degradation of this compound, the cleavage of ester bonds between octyl groups and sulphosuccinate, lasted significantly shorter time than the subsequent breakdown of the sulphosuccinate moiety of dioctyl sulpho[2,3-(14)C]succinate. (14)CO(2) evolution had a significant shorter lag period with cells in Tris/phosphate medium, without inorganic sulphate and adapted to surfactant, than unadapted cells. The acceleration of the primary degradation by adapted cells also suggest that some enzymes involved in surfactant degradation are inducible. The bacterium may be useful for bioremediation.

Adaptation, Physiological↗

PubMed2003

Comamonas testosteroni meningitis in a patient with recurrent cholesteatoma.

Comamonas testosteroni, a lesser-known member of the genus, has shown little apparent capacity for causing infections in humans. We here present a case of purulent meningitis due to C. testosteroni, which occurred in a patient who had recurrent cholesteatoma. Ceftriaxone treatment was not effective in this patient even though in vitro the bacteria were susceptible to the drug. The patient responded well to meropenem therapy.

Anti-Bacterial Agents↗

PubMed2003

The conserved cis-Pro39 residue plays a crucial role in the proper positioning of the catalytic base Asp38 in ketosteroid isomerase from Comamonas testosteroni.

KSI (ketosteroid isomerase) from Comamonas testosteroni is a homodimeric enzyme that catalyses the allylic isomerization of Delta5-3-ketosteroids to their conjugated Delta4-isomers at a reaction rate equivalent to the diffusion-controlled limit. Based on the structural analysis of KSI at a high resolution, the conserved cis-Pro39 residue was proposed to be involved in the proper positioning of Asp38, a critical catalytic residue, since the residue was found not only to be structurally associated with Asp38, but also to confer a structural rigidity on the local active-site geometry consisting of Asp38, Pro39, Val40, Gly41 and Ser42 at the flexible loop between b-strands B1 and B2. In order to investigate the structural role of the conserved cis-Pro39 residue near the active site of KSI, Pro39 was replaced with alanine or glycine. The free energy of activation for the P39A and P39G mutants increased by 10.5 and 16.7 kJ/mol (2.5 and 4.0 kcal/mol) respectively, while DG(U)H2O (the free-energy change for unfolding in the absence of urea at 25.00+/-0.02 degrees C) decreased by 31.0 and 35.6 kJ/mol (7.4 and 8.5 kcal/mol) respectively, compared with the wild-type enzyme. The crystal structure of the P39A mutant in complex with d-equilenin [d-1,3,5(10),6,8-estrapentaen-3-ol-17-one], a reaction intermediate analogue, determined at 2.3 A (0.23 nm) resolution revealed that the P39A mutation significantly disrupted the proper orientations of both d-equilenin and Asp38, as well as the local active-site geometry near Asp38, which resulted in substantial decreases in the activity and stability of KSI. Upon binding 1-anilinonaphthalene-8-sulphonic acid, the fluorescence intensities of the P39A and P39G mutants were increased drastically, with maximum wavelengths blue-shifted upon binding, indicating that the mutations might alter the hydrophobic active site of KSI. Taken together, our results demonstrate that the conserved cis-Pro39 residue plays a crucial role in the proper positioning of the critical catalytic base Asp38 and in the structural integrity of the active site in KSI.

Androstenedione↗

PubMed2004

A novel outer-membrane anion channel (porin) as part of a putatively two-component transport system for 4-toluenesulphonate in Comamonas testosteroni T-2.

Inducible mineralization of TSA (4-toluenesulphonate) by Comamonas testosteroni T-2 is initiated by a secondary transport system, followed by oxygenation and oxidation by TsaMBCD to 4-sulphobenzoate under the regulation of TsaR and TsaQ. Evidence is presented for a novel, presumably two-component transport system (TsaST). It is proposed that TsaT, an outer-membrane porin, formed an anion-selective channel that works in co-operation with the putative secondary transporter, TsaS, located in the inner membrane. tsaT was identified as a 1017-bp ORF (open reading frame) on plasmid pTSA upstream of the TSA-catabolic genes in the tsa operon. Expression of tsaT was regulated by TsaR, the transcriptional activator of the tsa regulon. The presence of tsaT was concomitant with the presence of the tsa operon in different TSA-degrading isolates. tsaT was expressed in Escherichia coli and was detected in the outer membrane. A 22-amino-acid leader peptide was identified. Purified protein reconstituted in lipid bilayer membranes formed anion-selective channels with a single-channel conductance of 3.5 nS in 1 M KCl. Downstream of tsaT, a constitutively expressed 720-bp ORF (tsaS) was identified. tsaS coded for a hydrophobic protein predicted to have six transmembrane helices and which is most likely localized in the cytoplasmic membrane. tsaS is adjacent to tsaT, but showed a different transcriptional profile.

Benzenesulfonates↗

PubMed1999

Adaptation of Comamonas testosteroni TA441 to utilization of phenol by spontaneous mutation of the gene for a trans-acting factor.

Comamonas testosteroni TA441 adapts to utilization of phenol upon incubation with phenol as the major carbon source. Strain TA441 has a cluster of genes (aphKLMNOPQB) encoding the catabolic enzymes phenol hydroxylase and catechol 2,3-dioxygenase, and a divergently transcribed regulatory gene (aphR), but these genes are silent until adaptation occurs. We found another regulatory gene (aphS) downstream of aphR. AphS belongs to the GntR family of transcriptional regulators. All adapted strains were found to have mutations in the aphS gene or in the aphR-aphS intervening region. The adapted strains expressed phenol hydroxylase and catechol 2, 3-dioxygenase activity in the presence of phenol. The transcriptional activity of both the aphK and the aphR promoters was elevated in the adapted strains. A strain whose aphS gene was artificially disrupted was found to be able to grow using phenol, and the cells showed high levels of the above-mentioned transcriptional and enzymatic activities, indicating that adaptation was caused only by the mutation in the aphS gene. Gel retardation analysis revealed that AphS bound to two specific sites in the promoter region between aphK and aphR. These results indicate that the active aphS gene product acts as a trans-acting factor and represses transcription of the aph genes in strain TA441.

Adaptation, Physiological↗

PubMed2003

Factors involved in the assembly of a functional molybdopyranopterin center in recombinant Comamonas acidovorans xanthine dehydrogenase.

Previous work from this laboratory has shown that the spectral and functional properties of a prokaryotic xanthine dehydrogenase from Comamonas acidovorans show some similarities to those of the well-characterized eukaryotic enzymes isolated from bovine milk and from chicken liver [Xiang, Q. & Edmondson, D.E. (1996) Biochemistry35, 5441-5450]. Therefore, this system was chosen to study the factors involved in the expression of functional recombinant enzyme in Escherichia coli to provide insights into the assembly of the functional Mo-pyranopterin center. Genes xdhA and xdhB (encoding the two known subunits of the native enzyme) and putative genes xprA and ssuABC were sequenced. Heterologous expression of the xdhAB genes in E. coli JM109(DE3) produced active enzyme. The Mo content was 0.11-0.16 mol per alphabeta protomer, while the Fe and FAD levels were at stoichiometries similar to that of the native enzyme. The XDH activity increased sixfold when the culture was grown under conditions of low aeration (6 L.min-1) as compared with high aeration (12 L.min-1). Co-expression of the xdhAB genes with the Pseudomonas aeruginosa PA1522 (xdhC) gene increased the level of Mo incorporated into the expressed enzyme to a 1 : 1 stoichiometry. Under these conditions, high levels of functional protein (2.284 U.mg-1 and 8.039 mg.L-1 of culture) were obtained independently of the level of culture aeration. Therefore, the assembly of a functional Mo-pyranopterin center in XDH requires the presence of a functional xdhC gene product. The purified, recombinant XDH shows spectral and kinetic properties identical to those of the native enzyme.

Amino Acid Sequence↗

PubMed2001

Regulation of the steroid-inducible 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase gene in Comamonas testosteroni.

The Comamonas testosteroni 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase gene (hsdA) codes for an adaptive enzyme in the degradation of steroid compounds. However, no information was available on the molecular regulation of steroid-inducible genes nor on the mechanism of steroid signaling in procaryotes. We, therefore, investigated the cis- and trans-acting elements of hsdA expression to infer the mechanism of its molecular regulation by steroids. The gene was localized on a 5.257-kilobase EcoRI fragment of C. testosteroni chromosomal DNA. The promoter was characterized, and the transcriptional start site was identified. Two palindromic operator domains were found upstream of hsdA. A new gene coding for a trans-acting negative regulator (repressor A, RepA) of hsdA expression was characterized. The specific interaction between RepA, testosterone, and the operator domain is demonstrated. From our results we conclude that hsdA is under negative transcriptional control by an adjacent gene product (RepA). Accordingly, induction of hsdA by steroids in fact is a derepression, where steroidal inducers bind to the repressor, thereby preventing its binding to the hsdA operator.

Alcohol Oxidoreductases↗