Phenazine-l-carboxylate

The best-studied system producing antibiotics in the rhizosphere are fluorescent pseudomonads, producing up to seven different compounds, as summarized in Fig. 9 2-hydroxyphenazine-l-carboxylate, phenazine-l-carboxylate, 2-hydroxy-phenazine, pyrrolnitrin, pyocyanine, 2.4-diacetylphloroglucinol. and pyoluteorin (48). Nine genes have been identified in the synthesis of phenazine-1-carboxylic... 

Rapid and sensitive HPLC methods were developed for the detection of an antimicrobial growth promoter and its main metabolites containing quinoxaline-2-carboxylic acid <2005MI1495>. The major phenazine pigments of Pseudomonas aeruginosa such as 1-hydroxyphenazine and phenazine-l-carboxylic acid <1997JCH(A)(771)99>, and 2-aminophenazine as an impurity in a bactericide <1999MI632>, were also analyzed by HPLC methods. 

Several phenazine derivatives, e.g. phenazin-2-ol, phenazine-l-carboxylic acid, 2-hydroxy-phenazine-1-carboxylic acid, phenazine-2,3-diol, and 2,3-dihydroxyphenazine-l-carboxylic acid have been isolated from Pseudomonas aureofaciens. 

Antibiotics such as pyoluteorin, pyrrolnitrin, phenazine-l-carboxylate, and 2,4-diacetylphloroglucinol are produced in the spermosphere and rhizosphere and play an important role in suppression of soil-borne plant pathogens. Suppression in a number of cases studied correlates with the production in the soil of the antibiotics. 

Figure 2. Chromatogram of a standard mixture of compounds (A) and corresponding circulating nutrient sample solution after SLM extraction (B). (1) p-Hydroxybenzoic acid, (2) vanillic acid, (3) salicylic acid, (4) benzoic acid, (5) ferulic acid, and (6) phenazine-l-carboxylic acid. The chromatogram additionally contains a number of other compounds. (Reproduced with permission from reference 28. Copyright 2002 Elsevier.)...

It follows from the above evidence that one of the hydroxy-groups in iodinin (180) is present before formation of the phenazine ring system. Accordingly, a highly efficient incorporation of 6-hydroxy-[7,9- H2]phenazine-l-carboxylic acid (as 179) into iodinin (180) was found. It thus appears probable that B. iodinum converts (170) and (179) by the same or similar enzyme systems into (178) and iodinin (180), respectively, N-oxide formation occurring either before or after hydroxylative decarboxylation. The two acids, (170) and (179), may well arise from the same (non-aromatic) precursor, by alternative aromatization reactions. 

Timms Wilson, T.M., Ellis, R.J., Renwick, A., Rhodes, D.J., Mavrodi, D.V., Weller, D.M., Thomashow, L.S., Bailey, M J. Chromosomal insertion of phenazine-1 -carboxylic acid biosynthetic pathway enhances efficacy of damping-off disease control by Pseudomonas fluorescens. Mol Plant-Microbe Interact 2000 13 1293-300. 

Using ether-treated cells of P. aureofaciens, dicarbonyl-14C2 phenazme-l,6-dicarboxylic acid las (121)1 was found to be an efficient and specific precursor for phenazine-1-carboxylic acid (123), and also for 2-hydroxyphenazine-l-carboxylic acid (124). The rate of growth of the organism appeared to be important, because an incorporation was also recorded of the labelled (121) into (123), albeit at a lower level, with cultures that had been grown rapidly. The position of phenazine-1,6-dicarboxylic acid (121) as a universal intermediate in the biosynthesis of phenazines now seems secure. The previously reported failure of dimethyl phenazine-1,6-dicarboxylate (122) to act as a precursor of phenazines cf. Vol. 10, p. 28 Vol. 9, p. 29) has been confirmed with ether-treated cells of P. aureofaciens. Efficient hydrolysis of (125) to (123) did, however, occur.101... 

Simulation of biosynthesis of phenazine pigments through the dimerization of substituted anilines by symmetrical carbon carbon pairing leads to substituted phenazines. Thus, oxidation of anthranilic acid with manganese(IV) oxide or lead(IV) oxide affords phenazine-l,6-di-carboxylic acid in 16% yield. ... 

Phenazine-1,6-dicarboxylic acid (1) is a precursor for microbiological transformation to phenazine-6-carboxylic acid. " - Decarboxylation of phenazine-l,6-dicarboxylic acid (1) in refluxing diphenyl ether affords a mixture of phenazine (2 yield 33%) and phenazine-l-car-boxylic acid (3 yield 25% mp 242-243... 

Phoiazines.— DL-[l,6- " C2]Shikimic acid [as (175)] is a specific precursor for pyocyanin (176) and phenazine-1-carboxylic acid (177) in Pseudomonas species. The activity was found to be approximately equally divided between the two groups of atoms C-1, C-4, C-6, and C-9 and C-4a, C-5a, C-9a, and C-lOa [see (177)]. Additional, more definitive, results were subsequently obtained with d-[6- C] shikimic acid activity in the derived phenazine-1-carboxylic acid was confined to C-4a, C-5a, C-9a, and C-lOa. 

The results obtained for iodinin (178) with and D-[l,6,7- C3]shikimic acids and for phenazine-1-carboxylic acid (177) with and DL-[l,6- C2]shikimic acids are now in agreement with... 

Phenazines.—Consideration of structural relationships between the various microbial phenazines, in association with evidence on the way in which these metabolites are formed from two molecules of shikimic acid (151), leads to phenazine-l,6-dicarboxylic acid (152) as a likely common intermediate (Scheme 8), but it has not been found to act as a precursor for various phenazines, exemplified by phenazine-1-carboxylic acid (153). Although the dimethyl ester of (152) has been reported to be a precursor for (153) in Pseudomonas aureo-faciens, it could not be confirmed as such under various conditions. The dihydro-derivative (156) was likewise found not to be a precursor for (153) and (154) in P. aureofaciens. ... 

Hou, C.T., L.K. Nakamura, D. Weisleder, R.E. Peterson, and M.O. Bagby, Identification of NRRL Strain B-18602 (PR3) as Pseudomonas aeruginosa and Effect of Phenazine-1 -carboxylic Acid Formation on 7,10-Dihydroxy-8( )-octadecenoic Acid Accumulation, World J. Microbiol. Biotechnol. 9 570-573 (1993). 

Studies of pyocyanin (3) production in Pseudomonas strains have shown that the biosynthetic transformations from phenazine-1-carboxylic acid (Ih) to pyocyanin (3) are highly consistent in fluorescent Pseudomonas sp. First, the 5-methylphenazine-1-carboxylic acid betaine (59) is formed by methylation of the 5-position on phenazine-1-carboxylic acid, catalyzed by SAM-dependent (5-adenosyl-L-methion-ine) methyltranferase, and subsequently an NADPH-dependent flavoprotein monooxygenase catalyzes the hydroxylative decarboxylation (Scheme 3). ° 5-Meth-ylphenazine-1-carboxylic acid betaine (59) is also... 

Hydroxyphenazine-l-carboxylic acid (li) and 2-hy-droxyphenazine (lb) are believed to be derived sequentially from phenazine-1-carboxylic acid (Ih) via known biotransformation reactions, presumably via an arene oxide intermediate (Scheme 3). In Pseudomonas aureofaciens, an NADPH-dependent reductase is responsible for the hydroxylation to form li, whereas the subsequent decarboxylation to give lb occurs spontaneously and nonenzymatically. ... 

Phenazine-1-carboxylic acid, 2-hydroxyphenazine, and 2-hydroxyphenazine-l-carboxylic acid were extracted from Pseudamonas aureofaciens cultures and analyzed on a Cig column (A = 257 nm) using a 25-min 65/35/0.1 ->0/100/0.1 water/acetonitrile/TFA gradient [1001]. Elution of the components is complete in 15 min and the two carboxylic acids are not resolved using this gradient system. Therefore, it seems prudent to change to a shallower gradient or have an initial isocratic hold period prior to a gradient in order to force a separation. 

In 2013, along with the reports of biologically active compounds, derived by targeted syntheses, a multitude of natural products was found to display antibacterial, antifungal, and anticancer activities. Mehnaz and her colleagues isolated and characterized known compounds phenazine-1-carboxylic acid (159), 2-hydroxyphenazine-l-carboxylic acid (160), 2-hydroxyphenazine (161), and 2,8-dihydroxyphenazine (162) from the biocontrol strain Pseudomonas aurantiaca PB-St2 (Figure 7-9) (13JNP135). 

Analogous feeding experiments with Pseudomonas aureofaciens established that (87) but not (88) was utilised in the formation of 2-hydroxyphenazine-l-carboxylic acid (94) and 2-hydroxyphena-zine (95). These results were interpreted as showing that both of these phenazine metabolites (94 and 95) are metabolites of phenazine-1-carboxylic acid (87) and are formed as outlined above. 

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