A-ketoglutarate dioxygenases

Matheson VG, LJ, Forney, Y Suwa, CH Nakatsu, AJ Sextone, AJ, WE Holben (1996) Evidence for acquisition in nature of a chromosomal 2,4-dichlorophenoxyacetic acid/a-ketoglutarate dioxygenase gene by different Burckholderia spp. Appl Environ Microbiol 62 2457-2463. 

Suwa Y, WE Olben, LJ Eorney (1996) Characterization of chromosomally encoded 2,4-dichlorophenoxyace-tic acid-a-ketoglutarate dioxygenase from Burkholderia sp. strain RASC. Appl Environ Microbiol 62 2464-2469. 

Sassanella TM, F Fukumori, M Bagdasarian, RP Hausinger (1997) Use of 4-nitrophenoxyacetic acid for detection and quantification of 2,4-dichlorophenoxyacetic acid 2,4-D/a-ketoglutarate dioxygenase activity in 2,4- D-degrading microorganisms. Appl Environ Microbiol 63 1189-1191. 

An elegant study by Ortiz de Montellano and Kunze strongly suggests that oxirenes are formed as intermediates in the oxidation of alkynes by microsomes <80JA7373>. 5-Ethynyluracil has been shown to act as a potent mechanism-based inhibitor of thymine 7-hydroxylase, an a-ketoglutarate dioxygenase the intermediacy of an oxirene has been proposed for the inactivation mechanism... 

The resonance Raman spectra of Fe(IV) complexes [(L)FeO]2+, where L = pentadentate pyridylamine ligands, include vFe=0 at 752 cm-1.298 Transient resonance Raman spectra of oxygen intermediates in the non-haem iron enzyme taurine/a-ketoglutarate dioxygenase, include characteristic bands at 812 (160)/787 (lsO) cm-1 and 583 (160)/555 (lsO) cm-1.299 Oxidised intermediates of cytochrome c oxidase give resonance Raman bands for vFe=0 showing that there are three different forms present.300... 

The 2,4-dichlorophenoxyacetic acid/a-ketoglutarate dioxygenase could accept 4-nitrophenoxyacetic acid to produce colored 4-nitro-phenol (Sassanella et al. 1997). It was pointed out, however, that a number of strains that were able to degrade 2,4-dichlorophenoxy-acetic acid were unable to accept the surrogate substrate. 

Eichhorn E, JR van der Ploeg, MA Kertesz, T Leisinger (1997) Characterization of an a-ketoglutarate-depen-dent taurine dioxygenase from Escherichia coli. J Biol Chem 272 23031-23036. 

Fukumori F, RP Hausinger (1993a) Alcaligenes eutrophus JMP 134 2,4-chlorophenoxyacetate monooxygenase is an a-ketoglutarate-dependent dioxygenase. J Bacterial 175 2083-2086. 

Nickel K, MJ-E Suter, H-PE Kophler (1997) Involvement of two a-ketoglutarate-dependent dioxygenases in enantioselective degradation of (R)- and (5)-mecoprop by Sphingomonas herbicidovorans MH. Appl Environ Microbiol 63 6674-6679. 

Stubbe J (1985) Identification of two a-ketoglutarate-dependent dioxygenases in extracts of Rhodotolula glutinis catalyzing deoxyuridine hydroxylation J Biol Chem 260 9972-9975. 

This enzyme [EC 1.14.11.7], also known as procolla-gen proline, 2-oxoglutarate 3-dioxygenase, catalyzes the reaction of a prolyl residue in procoUagen with dioxygen and a-ketoglutarate (or, 2-oxoglutarate) to produce a irans-3-hydroxyprolyl residue in procollagen, succinate, and carbon dioxide. This reaction also requires iron ions and ascorbate. 

The mechanism of a-ketoglutarate participation in the dioxygenase reaction has been proposed by Lindstedt and his co-workers6S,220) as shown in Eq. (27) with y-butyrobetaine hydroxylase. 

A very different but equally direct mechanism is used to repair 1-methyladenine and 3-methylcytosine. The amino groups of A and C residues are sometimes methylated when the DNA is single-stranded, and the methylation directly affects proper base pairing. In E. coli, oxidative demethylation of these alkylated nucleotides is mediated by the AllcB protein, a member of the a-ketoglutarate-Fe2+-dependent dioxygenase superfamily (Fig. 25-27). (See Box 4-3 for a description of another member of this enzyme family.)... 

FIGURE 25-27 Direct repair of alkylated bases by AlkB. The AlkB protein is an a-ketoglutarate-Fe2+-dependent dioxygenase. It catalyzes the oxidative demethylation of 1-methyladenine and 3-methyl-cytosine residues. 

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