Demethylation of Veratrole by Cytochrome P-450 in Streptomyces setonii

Abstract

The actinomycete Streptomyces setonii 75Vi2 demethylates vanillic acid and guaiacol to protocatechuic acid and catechol, respectively, and then metabolizes the products by the ,-ketoadipate pathway. UV spectroscopy showed that this strain could also metabolize veratrole (1,2-dimethoxybenzene). When grown in veratrolecontaining media supplemented with 2,2'-dipyridyl to inhibit cleavage of the aromatic ring, S. setonii accumulated catechol, which was detected by both liquid chromatography and gas chromatography. Reduced cell extracts from veratrole-grown cultures, but not sodium succinate-grown cultures, produced a carbon monoxide difference spectrum with a peak at 450 nm that indicated the presence of soluble cytochrome P-450. Addition of veratrole or guaiacol to oxidized cell extracts from veratrole-grown cultures produced difference spectra that indicated that these compounds were substrates for cytochrome P-450. My results suggest that S. setonii produces a cytochrome P-450 that is involved in the demethylation of veratrole and guaiacol to catechol, which is then catabolized by the 1-ketoadipate pathway.

Purification and characterization of cytochrome P450RR1 from Rhodococcus rhodochrous

“…A P450 from Moraxella sp. strain GU2 catalyzes the 0-dealkylation of 2-methoxyphenol (Dardas et al, 1985), that of Streptomyces setonii catalyzes two successive 0-dealkylations of veratrole (Sutherland, 1986) and a P450 that occurs in Nocardia sp. catalyzes the 0-dealkylation of 4-methoxybenzoate (Cartwright et al, 1971).…”

Transformations of chloroguaiacols, chloroveratroles, and chlorocatechols by stable consortia of anaerobic bacteria

“…The de-O-methylation, however, is clearly different in the two groups of organisms. The aerobic reaction is carried out by an oxygenase (3,6,46) with the formation of products at the oxidation level of formaldehyde, whereas the anaerobic reaction results in the synthesis of acetate with the methyl group intact (2, 12). On the other hand, dechlorination is presumably mediated by a reductase which might be common to both aerobic and anaerobic microorganisms.…”

Accelerating pathway evolution by increasing the gene dosage of chromosomal segments

“…A protein variant, which emerged from Evolution by Amplification and Synthetic biology, is beneficial in a different bacterium, indicating the broad utility of the method. carbon source (20)(21)(22)(23)(24)(25)(26). This substrate is enzymatically converted to formaldehyde and catechol, which can be further metabolized (Fig.…”

“…1B). Although the enzyme responsible for demethylation was partially characterized and used to obtain the N-terminal protein sequence (20)(21)(22)(23)(24)(25)(26), the corresponding genes were not identified. With database searches, we discovered gene products in Rhodococcus species that match the 21 N-terminal amino acid sequence previously determined for a guaiacol O-demethylating cytochrome P450 enzyme from Rhodococcus rhodochrous, P450 RR1 (21).…”