Unusual Oligomeric Laccase-like Oxidases from Ascomycete VKM F-3561 Polymerizing Phenylpropanoids and Phenolic Compounds under Neutral Environmental Conditions.

The unique oligomeric alkaliphilic laccase-like oxidases of the ascomycete VKM F-3561 (with molecular masses about 1035 and 870 kDa) were purified and characterized for the first time. The ability of the enzymes to oxidize phenylpropanoids and phenolic compounds under neutral environmental conditions with the formation of previously unknown di-, tri-, and tetrameric products of transformation was shown. The possibility to obtain industrially valuable compounds (dihydroxybenzyl alcohol and hydroxytyrosol) from caffeic acid using laccase-like oxidases of VKM F-3561 has been shown.

The Laccase of Myrothecium roridum VKM F-3565: A New Look at Fungal Laccase Tolerance to Neutral and Alkaline Conditions.

Most of the currently known fungal laccases show their maximum activity under acidic environmental conditions. It is known that a decrease in the activity of a typical laccase at neutral or alkaline pH values is the result of an increase in the binding of the hydroxide anion to the T2/T3 copper center, which prevents the transfer of an electron from the T1 Cu to the trinuclear copper center. However, evolutionary pressure has resolved the existing limitations in the catalytic mechanism of laccase, allowing such enzymes to be functionally active under neutral/alkaline pH conditions, thereby giving fungi an advantage for their survival.

Gentisate 1,2-dioxygenase from the gram-positive bacteria Rhodococcus opacus 1CP: Identical active sites vs. different substrate selectivities.

Gentisate 1,2-dioxygenases belong to the class III ring-cleaving dioxygenases catalyzing key reactions of aromatic compounds degradation by aerobic microorganisms. In the present work, the results of complete molecular, structural, and functional investigations of the gentisate 1,2-dioxygenase (rho-GDO) from a gram-positive bacterium Rhodococcus opacus 1CP growing on 3-hydroxybenzoate as a sole source of carbon and energy are presented. The purified enzyme showed a narrow substrate specificity.

Role of surfactants in optimizing fluorene assimilation and intermediate formation by Rhodococcus rhodochrous VKM B-2469.

Biodegradation of fluorene by Rhodococcus rhodochrous VKM B-2469 was investigated and optimized by adding non-ionic surfactants to the liquid media. The utilization of 1-1.5% Tween 60 or 1% Triton X100 allowed to solubilize 1 mM fluorene over 150 times more than in water medium (from 9-11 microM to above 1.

Intradiol pathway of para-cresol conversion by Rhodococcus opacus 1CP.

The growth of Rhodococcus opacus 1CP in medium with different concentrations of p-cresol as the sole source of carbon and energy was studied. It was shown that the optimal concentration of p-cresol was 600 mg/L. The ability of this strain to transform practically all amounts of p-cresol to 4-methylcatechol followed by its utilization through ortho-pathway was shown.

Crystal structure of 3-chlorocatechol 1,2-dioxygenase key enzyme of a new modified ortho-pathway from the Gram-positive Rhodococcus opacus 1CP grown on 2-chlorophenol.

The crystal structure of the 3-chlorocatechol 1,2-dioxygenase from the Gram-positive bacterium Rhodococcus opacus (erythropolis) 1CP, a Fe(III) ion-containing enzyme specialized in the aerobic biodegradation of 3-chloro- and methyl-substituted catechols, has been solved by molecular replacement techniques using the coordinates of 4-chlorocatechol 1,2-dioxygenase from the same organism (PDB code 1S9A) as a starting model and refined at 1.9 A resolution (R(free) 21.9%; R-factor 17.

Crystal structure of 4-chlorocatechol 1,2-dioxygenase from the chlorophenol-utilizing gram-positive Rhodococcus opacus 1CP.

The crystal structure of the 4-chlorocatechol 1,2-dioxygenase from the Gram-positive bacterium Rhodococcus opacus (erythropolis) 1CP, a Fe(III) ion-containing enzyme involved in the aerobic biodegradation of chloroaromatic compounds, has been solved by multiple wavelength anomalous dispersion using the weak anomalous signal of the two catalytic irons (1 Fe/257 amino acids) and refined at a 2.5 A resolution (R(free) 28.7%; R factor 21.

Conversion of 2-fluoromuconate to cis-dienelactone by purified enzymes of Rhodococcus opacus 1cp.

The present study describes the (19)F nuclear magnetic resonance analysis of the conversion of 3-halocatechols to lactones by purified chlorocatechol 1,2-dioxygenase (ClcA2), chloromuconate cycloisomerase (ClcB2), and chloromuconolactone dehalogenase (ClcF) from Rhodococcus opacus 1cp grown on 2-chlorophenol. The 3-halocatechol substrates were produced from the corresponding 2-halophenols by either phenol hydroxylase from Trichosporon cutaneum or 2-hydroxybiphenyl 3-mono-oxygenase from Pseudomonas azelaica. Several fluoromuconates resulting from intradiol ring cleavage by ClcA2 were identified.

Preliminary crystallographic analysis of 3-chlorocatechol 1,2-dioxygenase of a new modified ortho-pathway from the Gram-positive Rhodococcus opacus 1CP grown on 2-chlorophenol.

3-Chlorocatechol 1,2-dioxygenase (3-ClC1,2DO), a key enzyme of a new modified ortho-pathway, was isolated from a variant of the Gram-positive bacterium Rhodococcus opacus 1CP utilizing 2-chlorophenol as the sole energy and carbon source via a 3-chlorocatechol branch of a modified ortho-pathway. 3-ClC1,2DO catalyzes the intradiol cleavage of 3-chlorocatechol. The enzyme contains Fe(III) ions essential to the catalytic activity; it is a homodimer with a molecular weight of about 58 kDa composed of two identical subunits in an (alphaFe)(2)-type quaternary structure.

4-Chlorocatechol 1,2-dioxygenase from the chlorophenol-utilizing Gram-positive Rhodococcus opacus 1CP: crystallization and preliminary crystallographic analysis.

4-Chlorocatechol 1,2-dioxygenase (4-ClC1,2DO) from the Gram-positive bacterium Rhodococcus opacus (erythropolis) 1CP, an enzyme involved in the aerobic biodegradation of chloroaromatic compounds, has been crystallized. 4-ClC1,2DO, which specifically catalyzes the intradiol cleavage of 4-substituted catechols, which are intermediates in the degradation of a variety of aromatic pollutants, to the corresponding maleylacetates, has recently been purified to homogeneity. The enzyme is an homodimer composed of two identical subunits in an alpha(2)-type quaternary structure; it has a molecular weight of about 29 kDa per monomer and contains one Fe(III) and one Mn(II) ion per homodimer.