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Isolation and characterization of two novel halotolerant Catechol 2, 3-dioxygenases from a halophilic bacterial consortium.

Guo G, Fang T, Wang C, Huang Y, Tian F, Cui Q, Wang H - Sci Rep (2015)

Bottom Line: The enzymes activity both increased in the presence of Fe(3+), Fe(2+), Cu(2+) and Al(3+) and showed no significant inhibition by other tested metal ions.The optimal temperatures for the C23Os were 40 °C and 60 °C and their best substrates were catechol and 4-methylcatechol respectively.As the firstly isolated and characterized catechol dioxygenases from halophiles, the two halotolerant C23Os presented novel characteristics suggesting their potential application in aromatic hydrocarbons biodegradation.

View Article: PubMed Central - PubMed

Affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.

ABSTRACT
Study of enzymes in halophiles will help to understand the mechanism of aromatic hydrocarbons degradation in saline environment. In this study, two novel catechol 2,3-dioxygenases (C23O1 and C23O2) were cloned and overexpressed from a halophilic bacterial consortium enriched from an oil-contaminated saline soil. Phylogenetic analysis indicated that the novel C23Os and their relatives formed a new branch in subfamily I.2.A of extradiol dioxygenases and the sequence differences were further analyzed by amino acid sequence alignment. Two enzymes with the halotolerant feature were active over a range of 0-30% salinity and they performed more stable at high salinity than in the absence of salt. Surface electrostatic potential and amino acids composition calculation suggested high acidic residues content, accounting for their tolerance to high salinity. Moreover, two enzymes were further characterized. The enzymes activity both increased in the presence of Fe(3+), Fe(2+), Cu(2+) and Al(3+) and showed no significant inhibition by other tested metal ions. The optimal temperatures for the C23Os were 40 °C and 60 °C and their best substrates were catechol and 4-methylcatechol respectively. As the firstly isolated and characterized catechol dioxygenases from halophiles, the two halotolerant C23Os presented novel characteristics suggesting their potential application in aromatic hydrocarbons biodegradation.

No MeSH data available.


Related in: MedlinePlus

Effect of temperature on C23O activity (a), and thermal stability of C23O1 (b) and C23O2 (c). The values shown represent averages from triplicate experiments. Error bars represent the standard deviation.
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f5: Effect of temperature on C23O activity (a), and thermal stability of C23O1 (b) and C23O2 (c). The values shown represent averages from triplicate experiments. Error bars represent the standard deviation.

Mentions: The influence of reaction temperature on enzyme activity was investigated at the temperatures range of 0–90 °C using catechol as substrate. The two enzymes showed different optimal temperature: C23O1 demonstrated a high optimal temperature of 40 °C, while C23O2 required a temperature of 60 °C to exhibit the maximal activity (Fig. 5a). What’s more, the specific activity of C23O1 was 1.9 times as much as that of C23O2 at the optimal temperature. In addition, the C23O2 activity could still be detected at 80 °C with 54% of activity at the optimal temperature. In the test of temperature effect on time-dependent activity (Fig. 5b,c), the results showed the similiar trends between the two C23Os that they were both highly stable in the temperature range of 4–30 °C for 24 h. Their activities were kept best at 10 °C and the residual activities were about 80% at 24 h, followed by 20 °C with approximately 60% residual activies at 24 h. Their enzyme activities declined rapidly as the temperature increased above 50 °C.


Isolation and characterization of two novel halotolerant Catechol 2, 3-dioxygenases from a halophilic bacterial consortium.

Guo G, Fang T, Wang C, Huang Y, Tian F, Cui Q, Wang H - Sci Rep (2015)

Effect of temperature on C23O activity (a), and thermal stability of C23O1 (b) and C23O2 (c). The values shown represent averages from triplicate experiments. Error bars represent the standard deviation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664950&req=5

f5: Effect of temperature on C23O activity (a), and thermal stability of C23O1 (b) and C23O2 (c). The values shown represent averages from triplicate experiments. Error bars represent the standard deviation.
Mentions: The influence of reaction temperature on enzyme activity was investigated at the temperatures range of 0–90 °C using catechol as substrate. The two enzymes showed different optimal temperature: C23O1 demonstrated a high optimal temperature of 40 °C, while C23O2 required a temperature of 60 °C to exhibit the maximal activity (Fig. 5a). What’s more, the specific activity of C23O1 was 1.9 times as much as that of C23O2 at the optimal temperature. In addition, the C23O2 activity could still be detected at 80 °C with 54% of activity at the optimal temperature. In the test of temperature effect on time-dependent activity (Fig. 5b,c), the results showed the similiar trends between the two C23Os that they were both highly stable in the temperature range of 4–30 °C for 24 h. Their activities were kept best at 10 °C and the residual activities were about 80% at 24 h, followed by 20 °C with approximately 60% residual activies at 24 h. Their enzyme activities declined rapidly as the temperature increased above 50 °C.

Bottom Line: The enzymes activity both increased in the presence of Fe(3+), Fe(2+), Cu(2+) and Al(3+) and showed no significant inhibition by other tested metal ions.The optimal temperatures for the C23Os were 40 °C and 60 °C and their best substrates were catechol and 4-methylcatechol respectively.As the firstly isolated and characterized catechol dioxygenases from halophiles, the two halotolerant C23Os presented novel characteristics suggesting their potential application in aromatic hydrocarbons biodegradation.

View Article: PubMed Central - PubMed

Affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.

ABSTRACT
Study of enzymes in halophiles will help to understand the mechanism of aromatic hydrocarbons degradation in saline environment. In this study, two novel catechol 2,3-dioxygenases (C23O1 and C23O2) were cloned and overexpressed from a halophilic bacterial consortium enriched from an oil-contaminated saline soil. Phylogenetic analysis indicated that the novel C23Os and their relatives formed a new branch in subfamily I.2.A of extradiol dioxygenases and the sequence differences were further analyzed by amino acid sequence alignment. Two enzymes with the halotolerant feature were active over a range of 0-30% salinity and they performed more stable at high salinity than in the absence of salt. Surface electrostatic potential and amino acids composition calculation suggested high acidic residues content, accounting for their tolerance to high salinity. Moreover, two enzymes were further characterized. The enzymes activity both increased in the presence of Fe(3+), Fe(2+), Cu(2+) and Al(3+) and showed no significant inhibition by other tested metal ions. The optimal temperatures for the C23Os were 40 °C and 60 °C and their best substrates were catechol and 4-methylcatechol respectively. As the firstly isolated and characterized catechol dioxygenases from halophiles, the two halotolerant C23Os presented novel characteristics suggesting their potential application in aromatic hydrocarbons biodegradation.

No MeSH data available.


Related in: MedlinePlus