Dual activity of certain HIT‐proteins: <i>A. thaliana</i> Hint4 and <i>C. elegans</i> DcpS act on adenosine 5′‐phosphosulfate as hydrolases (forming AMP) and as phosphorylases (forming ADP)

Guranowski, Andrzej; Wojdyła, Anna Maria; Zimny, Jarosław; Wypijewska, Anna; Kowalska, Joanna; Jemielity, Jacek; Davis, Richard E.; Bieganowski, Paweł

doi:10.1016/j.febslet.2009.11.003

Cited by 19 publications

(19 citation statements)

References 19 publications

(23 reference statements)

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“…The supposition that NH 2 -pA occurs in other organisms and that its concentration can be enzymatically controlled is supported by the existence of adenosine-, or generally nucleoside-5′-phosphoramidate hydrolases (EC 3.9.1.-) that catalyze cleavage of the substrate P-N bond and liberate the corresponding 5′-NMP (pN) and ammonia from NH 2 -pA or other NH 2 -pNs. This catabolic activity has been demonstrated in D. discoideum (Rossomando & Hadjimichael, 1986), rat liver (Kuba et al, 1994), and appears to be a catalytic feature of various HIT-proteins (Bieganowski et al, 2002;Guranowski et al, 2008;2010a;2010b). Our preliminary studies showed that NH 2 -pA can be hydrolyzed by at least two enzymes from yellow lupin -dinucleoside triphosphatase/Fhit homolog protein (EC 3.6.1.29) and nucleoside phosphoramidase (Hint protein) (Guranowski et al, 2006).…”

Section: Introductionsupporting

confidence: 59%

Plant nucleoside 5'-phosphoramidate hydrolase; simple purification from yellow lupin (Lupinus luteus) seeds and properties of homogeneous enzyme.

et al. 2011

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Adenosine 5'-phosphoramidate (NH₂-pA) is an uncommon natural nucleotide of poorly understood biochemistry and function. We studied a plant enzyme potentially involved in the catabolism of NH₂-pA. A fast and simple method comprising extraction of yellow lupin (Lupinus luteus) seed-meal with a low ionic strength buffer, ammonium sulfate and acetone fractionations, removal of contaminating proteins by heat denaturation, and affinity chromatography on AMP-agarose, yielded homogenous nucleoside 5'-phosphoramidase. Mass spectrometric analysis showed that the lupin hydrolase exhibits closest similarity to Arabidopsis thaliana Hint1 protein. The substrate specificity of the lupin enzyme, in particular its ability to split the P-S bond in adenosine 5'-phosphorothioate, is typical of known Hint1 proteins. Adenosine 5'-phosphofluoride and various derivatives of guanosine 5'-phosphoramidate were also substrates. Neither common divalent metal cations nor 10 mM EDTA or EGTA affected the hydrolysis of NH₂-pA. The enzyme functions as a homodimer (2 x 15,800 Da). At the optimum pH of 7.0, the K(m) for NH₂-pA was 0.5 µM and k(cat) 0.8 s⁻¹ (per monomer active site). The properties of the lupin nucleoside 5'-phosphoramidase are compared with those of its counterparts from other organisms.

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Section: Introductionsupporting

confidence: 59%

Plant nucleoside 5'-phosphoramidate hydrolase; simple purification from yellow lupin (Lupinus luteus) seeds and properties of homogeneous enzyme.

et al. 2011

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“…In addition to C10F3.4 and C15orf58, a mycobacterial protein (Rv2613c) containing a HXHXH motif has also recently been reported to act as a phosphorylase (on diadenosine tetraphosphate) and not as a hydrolase (27). Furthermore, A. thaliana Hint4 and C. elegans DcpS, two HIT proteins containing the HXHXH motif, have been shown to display a phosphorolytic activity toward adenosine 5Ј-phosphosulfate in addition to their hydrolytic activity on this substrate (28). The phosphorylase activity of the latter two enzymes, however, was minor compared with their hydrolase activity at neutral pH.…”

Section: Discussionmentioning

confidence: 99%

A Novel GDP-d-glucose Phosphorylase Involved in Quality Control of the Nucleoside Diphosphate Sugar Pool in Caenorhabditis elegans and Mammals

Adler¹,

Gomez²,

Clarke³

et al. 2011

Journal of Biological Chemistry

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The plant VTC2 gene encodes GDP-L-galactose phosphorylase, a rate-limiting enzyme in plant vitamin C biosynthesis. Genes encoding apparent orthologs of VTC2 exist in both mammals, which produce vitamin C by a distinct metabolic pathway, and in the nematode worm Caenorhabditis elegans where vitamin C biosynthesis has not been demonstrated. We have now expressed cDNAs of the human and worm VTC2 homolog genes (C15orf58 and C10F3.4, respectively) and found that the purified proteins also display GDP-hexose phosphorylase activity. However, as opposed to the plant enzyme, the major reaction catalyzed by these enzymes is the phosphorolysis of GDP-D-glucose to GDP and D-glucose 1-phosphate. We detected activities with similar substrate specificity in worm and mouse tissue extracts. The highest expression of GDP-D-glucose phosphorylase was found in the nervous and male reproductive systems. A C. elegans C10F3.4 deletion strain was found to totally lack GDP-D-glucose phosphorylase activity; this activity was also found to be decreased in human HEK293T cells transfected with siRNAs against the human C15orf58 gene. These observations confirm the identification of the worm C10F3.4 and the human C15orf58 gene expression products as the GDP-D-glucose phosphorylases of these organisms. Significantly, we found an accumulation of GDP-D-glucose in the C10F3.4 mutant worms, suggesting that the GDP-D-glucose phosphorylase may function to remove GDP-D-glucose formed by GDP-D-mannose pyrophosphorylase, an enzyme that has previously been shown to lack specificity for its physiological D-mannose 1-phosphate substrate. We propose that such removal may prevent the misincorporation of glucosyl residues for mannosyl residues into the glycoconjugates of worms and mammals.The last missing enzyme of the plant vitamin C biosynthesis pathway was recently identified as a GDP-L-galactose phosphorylase encoded by the Arabidopsis VTC2 gene (1, 2). In this 10-step metabolic pathway from D-glucose to L-ascorbate, GDP-L-Gal 4 phosphorylase catalyzes the formation of L-Gal-1-P in the first committed (and highly regulated) step to vitamin C biosynthesis (2-5). Intriguingly, the VTC2 gene appears to be conserved in vertebrates, which are known to synthesize vitamin C via a different metabolic pathway than plants that does not include GDP-L-Gal as an intermediate (6), and in invertebrates such as Caenorhabditis elegans that may lack the ability to synthesize vitamin C (1). The physiological functions of these apparent orthologs are thus unclear. One clue may be that the Arabidopsis VTC2 enzyme can also use GDP-D-glucose as a substrate (1). Although the role of this activity in plants is unclear, such an activity may be important in other species. Whereas GDP-L-Gal is most probably absent from mammalian tissues, the presence of GDP-D-Glc in bovine mammary gland and the existence of a mammalian GDP-D-Glc pyrophosphorylase have been reported (7,8). More recent observations suggest that GDP-D-Glc formation can be catalyzed by the mammalian GDP-D-mannose pyroph...

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“…The occurrence of these proteins in peroxisomes appears to be a plant-specific phenomenon, as the Arabidopsis HIT PTSs are also conserved in their homologs in other plant species such as rice (Table 1). A recent in vitro study showed that most of the Arabidopsis HIT proteins can function as sulfohydrolases by catalyzing the conversion of adenosine 5′-phosphosulfate (APS) to AMP and sulfate (

{SO}_{4}^{2 -}

; Guranowski et al, 2010). This study also showed that, in the presence of orthophosphate (P i ), HIT1/Hint4 exhibited APS phosphorylase activity as well, resulting in the formation of ADP.…”

Section: Some Novel Aspects Of Plant Peroxisomes Revealed By Experimementioning

confidence: 99%

Defining the Plant Peroxisomal Proteome: From Arabidopsis to Rice

Kaur¹,

Hu²

2011

Front. Plant Sci.

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Peroxisomes are small subcellular organelles mediating a multitude of processes in plants. Proteomics studies over the last several years have yielded much needed information on the composition of plant peroxisomes. In this review, the status of peroxisome proteomics studies in Arabidopsis and other plant species and the cumulative advances made through these studies are summarized. A reference Arabidopsis peroxisome proteome is generated, and some unique aspects of Arabidopsis peroxisomes that were uncovered through proteomics studies and hint at unanticipated peroxisomal functions are also highlighted. Knowledge gained from Arabidopsis was utilized to compile a tentative list of peroxisome proteins for the model monocot plant, rice. Differences in the peroxisomal proteome between these two model plants were drawn, and novel facets in rice were expounded upon. Finally, we discuss about the current limitations of experimental proteomics in decoding the complete and dynamic makeup of peroxisomes, and complementary and integrated approaches that would be beneficial to defining the peroxisomal metabolic and regulatory roadmaps. The synteny of genomes in the grass family makes rice an ideal model to study peroxisomes in cereal crops, in which these organelles have received much less attention, with the ultimate goal to improve crop yield.

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Dual activity of certain HIT‐proteins: A. thaliana Hint4 and C. elegans DcpS act on adenosine 5′‐phosphosulfate as hydrolases (forming AMP) and as phosphorylases (forming ADP)

Cited by 19 publications

References 19 publications

Plant nucleoside 5'-phosphoramidate hydrolase; simple purification from yellow lupin (Lupinus luteus) seeds and properties of homogeneous enzyme.

Plant nucleoside 5'-phosphoramidate hydrolase; simple purification from yellow lupin (Lupinus luteus) seeds and properties of homogeneous enzyme.

A Novel GDP-d-glucose Phosphorylase Involved in Quality Control of the Nucleoside Diphosphate Sugar Pool in Caenorhabditis elegans and Mammals

Defining the Plant Peroxisomal Proteome: From Arabidopsis to Rice

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