Biosynthesis of riboflavin in plants. The ribA gene of Arabidopsis thaliana specifies a bifunctional GTP cyclohydrolase II/3,4-dihydroxy-2-butanone 4-phosphate synthase

Herz, Stefan; Eberhardt, Sabine; Bacher, Adelbert

doi:10.1016/s0031-9422(00)00013-3

Cited by 61 publications

(62 citation statements)

References 20 publications

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“…The enzyme properties were studied in the bacteria E. coli (35,123,206), B. subtilis (185), Helicobacter pylori (32), and Streptomyces coelicolor (461), the flavinogenic yeast P. guilliermondii (412,418,425), and the model plant Arabidopsis thaliana (174 (206,365). The reaction starts by pyrophosphate release, which appeared to be the rate-limiting step of the overall reaction, after which imidazole ring opening and elimination of formate occur (206,373).…”

Section: Gtp Cyclohydrolases II and Iiimentioning

confidence: 99%

“…The enzyme from E. coli is a homodimer with a molecular mass of 47 kDa (220,370). Similarly, in B. subtilis and plants 3,4-dihydroxy-2-butanone 4-phosphate synthase is the part of the fused protein also containing GTP cyclohydrolase II (113,174). GTP cyclohydrolase is located at the C-terminal end of the fused protein, whereas 3,4-dihydroxy-2-butanone 4-phosphate synthase occupies the N-terminal part of the protein.…”

Section: 4-dihydroxy-2-butanone 4-phosphate Synthasementioning

confidence: 99%

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Genetic Control of Biosynthesis and Transport of Riboflavin and Flavin Nucleotides and Construction of Robust Biotechnological Producers

Abbas

Sibirny

2011

Microbiol Mol Biol Rev

316

272

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SUMMARY Riboflavin [7,8-dimethyl-10-(1′- d -ribityl)isoalloxazine, vitamin B 2 ] is an obligatory component of human and animal diets, as it serves as the precursor of flavin coenzymes, flavin mononucleotide, and flavin adenine dinucleotide, which are involved in oxidative metabolism and other processes. Commercially produced riboflavin is used in agriculture, medicine, and the food industry. Riboflavin synthesis starts from GTP and ribulose-5-phosphate and proceeds through pyrimidine and pteridine intermediates. Flavin nucleotides are synthesized in two consecutive reactions from riboflavin. Some microorganisms and all animal cells are capable of riboflavin uptake, whereas many microorganisms have distinct systems for riboflavin excretion to the medium. Regulation of riboflavin synthesis in bacteria occurs by repression at the transcriptional level by flavin mononucleotide, which binds to nascent noncoding mRNA and blocks further transcription (named the riboswitch). In flavinogenic molds, riboflavin overproduction starts at the stationary phase and is accompanied by derepression of enzymes involved in riboflavin synthesis, sporulation, and mycelial lysis. In flavinogenic yeasts, transcriptional repression of riboflavin synthesis is exerted by iron ions and not by flavins. The putative transcription factor encoded by SEF1 is somehow involved in this regulation. Most commercial riboflavin is currently produced or was produced earlier by microbial synthesis using special selected strains of Bacillus subtilis , Ashbya gossypii , and Candida famata . Whereas earlier RF overproducers were isolated by classical selection, current producers of riboflavin and flavin nucleotides have been developed using modern approaches of metabolic engineering that involve overexpression of structural and regulatory genes of the RF biosynthetic pathway as well as genes involved in the overproduction of the purine precursor of riboflavin, GTP.

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Section: Gtp Cyclohydrolases II and Iiimentioning

confidence: 99%

Section: 4-dihydroxy-2-butanone 4-phosphate Synthasementioning

confidence: 99%

Genetic Control of Biosynthesis and Transport of Riboflavin and Flavin Nucleotides and Construction of Robust Biotechnological Producers

Abbas

Sibirny

2011

Microbiol Mol Biol Rev

316

272

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“…However, little is known about the enzymes responsible for the turnover and membrane transport of riboflavin and flavin nucleotides, despite the crucial roles of these nucleotides in metabolism in plants. Three of the plant enzymes involved in the biosynthesis of the riboflavin precursor [lumazine synthase, bifunctional GTP cyclohydrolase II/3,4-dihydrozy-2-butane 4-phosphate synthase, and 2,5-diamino-6-ribosylamino-4(3H)-pyrimidine 5-phosphate deaminase] have been characterized from Arabidopsis (Jordan et al, 1999;Herz et al, 2000;Fischer et al, 2004). Interestingly, the deduced amino acid sequences of all of these enzymes contain chloroplast transit peptides.…”

Section: Fad Pyrophosphohydrolasementioning

confidence: 99%

Molecular Characterization of Organelle-Type Nudix Hydrolases in Arabidopsis

et al. 2008

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Nudix (for nucleoside diphosphates linked to some moiety X) hydrolases act to hydrolyze ribonucleoside and deoxyribonucleoside triphosphates, nucleotide sugars, coenzymes, or dinucleoside polyphosphates. Arabidopsis (Arabidopsis thaliana) contains 27 genes encoding Nudix hydrolase homologues (AtNUDX1 to -27) with a predicted distribution in the cytosol, mitochondria, and chloroplasts. Previously, cytosolic Nudix hydrolases (AtNUDX1 to -11 and -25) were characterized. Here, we conducted a characterization of organelle-type AtNUDX proteins (AtNUDX12 to -24, -26, and -27). AtNUDX14 showed pyrophosphohydrolase activity toward both ADP-ribose and ADP-glucose, although its K m value was approximately 100-fold lower for ADP-ribose (13.0 6 0.7 mM) than for ADP-glucose (1,235 6 65 mM). AtNUDX15 hydrolyzed not only reduced coenzyme A (118.7 6 3.4 mM) but also a wide range of its derivatives. AtNUDX19 showed pyrophosphohydrolase activity toward both NADH (335.3 6 5.4 mM) and NADPH (36.9 6 3.5 mM). AtNUDX23 had flavin adenine dinucleotide pyrophosphohydrolase activity (9.1 6 0.9 mM). Both AtNUDX26 and AtNUDX27 hydrolyzed diadenosine polyphosphates (n = 4-5). A confocal microscopic analysis using a green fluorescent protein fusion protein showed that AtNUDX15 is distributed in mitochondria and AtNUDX14 -19, -23, -26, and -27 are distributed in chloroplasts. These AtNUDX mRNAs were detected ubiquitously in various Arabidopsis tissues. The T-DNA insertion mutants of AtNUDX13,, and -27 did not exhibit any phenotypical differences under normal growth conditions. These results suggest that Nudix hydrolases in Arabidopsis control a variety of metabolites and are pertinent to a wide range of physiological processes.

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“…Certain microorganisms and plants were subsequently shown to specify bifunctional enzymes comprising GTP cyclohydrolase II and 3,4-dihydroxy-2-butanone 4-phosphate synthase domains (15).…”

mentioning

confidence: 99%

Biosynthesis of Riboflavin

Ritz

Schramek

Bracher

et al. 2001

Journal of Biological Chemistry

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GTP cyclohydrolase II catalyzes the first committed reaction in the biosynthesis of the vitamin riboflavin. The recombinant enzyme from Escherichia coli is shown to produce 2,5-diamino-6-␤-ribosylamino-4(3H)-pyrimidinone 5-phosphate and GMP at an approximate molar ratio of 10:1. The main product is subject to spontaneous isomerization affording the ␣-anomer.18 O from solvent water is incorporated by the enzyme into the phosphate group of the 5-aminopyrimidine derivative as well as GMP. These data are consistent with the transient formation of a covalent phosphoguanosyl derivative of the enzyme. Subsequent ring opening of the covalently bound nucleotide followed by hydrolysis of the phosphodiester bond could then afford the pyrimidine type product. The hydrolysis of the phosphodiester bond without prior ring opening could afford GMP. The enzyme reaction is cooperative with a Hill coefficient of 1.3. Inhibition by pyrophosphate is competitive. Inhibition by orthophosphate is partially uncompetitive at low concentration and competitive at concentrations above 6 mM.

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Biosynthesis of riboflavin in plants. The ribA gene of Arabidopsis thaliana specifies a bifunctional GTP cyclohydrolase II/3,4-dihydroxy-2-butanone 4-phosphate synthase

Cited by 61 publications

References 20 publications

Genetic Control of Biosynthesis and Transport of Riboflavin and Flavin Nucleotides and Construction of Robust Biotechnological Producers

Genetic Control of Biosynthesis and Transport of Riboflavin and Flavin Nucleotides and Construction of Robust Biotechnological Producers

Molecular Characterization of Organelle-Type Nudix Hydrolases in Arabidopsis

Biosynthesis of Riboflavin

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