Structural and biochemical characterization of GTP cyclohydrolase II from Helicobacter pylori reveals its redox dependent catalytic activity

Yadav, S.; Karthikeyan, Subramanian

doi:10.1016/j.jsb.2015.08.004

Cited by 10 publications

(12 citation statements)

References 68 publications

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“…6b ) with a K M of 66 ± 12 μM (SE) ( Fig. 4b ), which is close to what has been reported for other His-tagged GTP cyclohydrolase II enzymes ( 20 , 21 ). Then, we fed 13 C 10 , 15 N 5 -GTP to Hedin/2 roots to determine whether GTP was a precursor for vicine and convicine.…”

supporting

confidence: 89%

VC1 catalyses a key step in the biosynthesis of vicine in faba bean

et al. 2021

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Faba bean ( Vicia faba L.) is a widely adapted and high-yielding legume cultivated for its protein-rich seeds ( 1 ). However, the seeds accumulate the pyrimidine glucosides vicine and convicine, which can cause hemolytic anemia (favism) in 400 million genetically predisposed individuals ( 2 ). Here, we use gene-to-metabolite correlations, gene mapping, and genetic complementation to identify VC1 as a key enzyme in vicine and convicine biosynthesis. We demonstrate that VC1 has GTP cyclohydrolase II activity and that the purine GTP is a precursor of both vicine and convicine. Finally, we show that cultivars with low vicine and convicine levels carry an inactivating insertion in the coding sequence of VC1 . Our results reveal an unexpected, purine rather than pyrimidine, biosynthetic origin for vicine and convicine and pave the way for the development of faba bean cultivars that are free of these anti-nutrients.

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confidence: 89%

VC1 catalyses a key step in the biosynthesis of vicine in faba bean

et al. 2021

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“…3b ). These kinetic parameters resemble those of other functional GTP cyclohydrolase II enzymes 20, 21, 22 . Then, we fed 13 C 10 , 15 N 5 -GTP to Hedin/2 roots to determine whether GTP was a precursor for vicine and convicine.…”

Section: Main Textsupporting

confidence: 57%

“…Enzyme activity was analysed as previously reported 21, 22 . The reaction was carried out in 200 µl and contained 50 mM Tris at pH 8.0, 100 mM NaCl, 10 mM MgCl 2 and GTP at concentrations varying from 0-244 µM.…”

Section: Methodsmentioning

confidence: 99%

“…Conversion of GTP to the product 2,5-diamino-6-β-ribosyl-4(3 H )-pyrimidinone-5’-phosphate (DARPP) was monitored by measuring absorbance at 310 nm for 5 min using a microplate reader (Spectramax M5, Molecular Devices). The reaction rate was calculated using the extinction coefficient for DARPP (7.43 cm -1 mM -1 ) as previously reported 21, 22 . The kinetic parameters K M and V max were calculated by non-linear regression to fit the data to the Michaelis-Menten equation using Sigmaplot v13.0.…”

Section: Methodsmentioning

confidence: 99%

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VC1 catalyzes a key step in the biosynthesis of vicine from GTP in faba bean

Björnsdotter

Nadzieja

Chang

et al. 2020

Preprint

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25Faba bean is a widely adapted and high-yielding legume cultivated for its protein-rich seeds 1 . 26 However, the seeds accumulate the anti-nutritional pyrimidine glucosides vicine and convicine, which 27 can cause haemolytic anaemia-favism-in the 400 million individuals genetically predisposed by a 28 deficiency in glucose-6-phosphate dehydrogenase 2 . Here, we identify the first enzyme associated with 29 vicine and convicine biosynthesis, which we name VC1. We show that VC1 co-locates with the major QTL 30 for vicine and convicine content and that the expression of VC1 correlates highly with vicine content 31 across tissues. We also show that low-vicine varieties express a version of VC1 carrying a small, frame-32 shift insertion, and that overexpression of wild-type VC1 leads to an increase in vicine levels. VC1 33 encodes a functional GTP cyclohydrolase II, an enzyme normally involved in riboflavin biosynthesis from 34 the purine GTP. Through feeding studies, we demonstrate that GTP is a precursor of vicine both in faba 35 bean and in the distantly related plant bitter gourd. Our results reveal an unexpected biosynthetic origin 36 for vicine and convicine and pave the way for the development of faba bean cultivars that are free from 37 these anti-nutrients, providing a safe and sustainable source of dietary protein. 38 39 Main Text 40 According to the UN's Intergovernmental Panel on Climate Change (IPCC), switching to a plant-based 41 diet can reduce carbon emissions, especially in the West 3 . The suggested change in diet will require a wider 42and more varied cultivation of locally adapted protein crops. On a worldwide basis, faba bean ( Fig. 1a) has 43 the highest yield of the legumes after soybean (1.92 Mg/ha in 2013-2017) 4 and the highest seed protein 44 content of the starch-containing legumes (29% dry-matter basis) 5 . Furthermore, faba bean is adapted to 45 cool climates such as Mediterranean winters and northern European summers, where soybean performs 46 poorly 6 . The main factor restricting faba bean cultivation and consumption is the presence of the anti-47 2, Supplementary File 6). Using seed coat cDNA and PCR primers able to distinguish between VC1 and vc1, 132

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“…2a). It is not uncommon for an NTPase to co-purify with a pyrophosphate, as for example, in structures of KOKV NS3-Hel 8 and H.pylori GTP cyclohydrolase 9 . A β-hairpin extends from domain 2 and interacts with domain 3 and has been proposed to act as a “wedge” to help separate the RNA strands of dsRNA for the unwinding reaction (Fig.…”

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confidence: 99%

Structure of the NS3 helicase from Zika virus

Jain

Coloma

García‐Sastre

et al. 2016

Nat Struct Mol Biol

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The Zika virus has emerged as a pathogen of major health concern. We present a high-resolution (1.62Å) crystal structure of the RNA helicase from the French Polynesia strain. The structure is similar to that of the RNA helicase from Dengue virus, with variability in the conformations of loops typically involved in ATP and RNA binding. We identify druggable “hotspots” that are well-suited for in-silico and/or fragment-based high throughput drug discovery.

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Structural and biochemical characterization of GTP cyclohydrolase II from Helicobacter pylori reveals its redox dependent catalytic activity

Cited by 10 publications

References 68 publications

VC1 catalyses a key step in the biosynthesis of vicine in faba bean

VC1 catalyses a key step in the biosynthesis of vicine in faba bean

VC1 catalyzes a key step in the biosynthesis of vicine from GTP in faba bean

Structure of the NS3 helicase from Zika virus

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