Purine Biosynthesis. Big in Cell Division, Even Bigger in Nitrogen Assimilation

Smith, Penelope M. C.; Atkins, Craig A.

doi:10.1104/pp.010912

Cited by 192 publications

(176 citation statements)

References 40 publications

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“…Most of the enzymes of de novo purine synthesis have recently been isolated and purified. An unexpected finding was that, unlike higher animals where multifunctional enzymes are involved in the pathway, each step is catalyzed by a separate enzyme in nodules (Smith and Atkins, 2002). This situation resembles that found in prokaryotes.…”

Section: Relationship Of Soybean To Model Plantsmentioning

confidence: 87%

National Science Foundation-Sponsored Workshop Report. Draft Plan for Soybean Genomics

et al. 2004

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Recent efforts to coordinate and define a research strategy for soybean (Glycine max) genomics began with the establishment of a Soybean Genetics Executive Committee, which will serve as a communication focal point between the soybean research community and granting agencies. Secondly, a workshop was held to define a strategy to incorporate existing tools into a framework for advancing soybean genomics research. This workshop identified and ranked research priorities essential to making more informed decisions as to how to proceed with large scale sequencing and other genomics efforts. Most critical among these was the need to finalize a physical map and to obtain a better understanding of genome microstructure. Addressing these research needs will require pilot work on new technologies to demonstrate an ability to discriminate between recently duplicated regions in the soybean genome and pilot projects to analyze an adequate amount of random genome sequence to identify and catalog common repeats. The development of additional markers, reverse genetics tools, and bioinformatics is also necessary. Successful implementation of these goals will require close coordination among various working groups.

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Section: Relationship Of Soybean To Model Plantsmentioning

confidence: 87%

National Science Foundation-Sponsored Workshop Report. Draft Plan for Soybean Genomics

et al. 2004

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“…Purine biosynthesis is central to the biogenesis of many molecules critical for proper cellular metabolism including the DNA and RNA precursors AMP and GMP, the essential coenzymes NAD, NADP, FAD, and CoA, the signaling molecule cAMP, and the ubiquitous energy source ATP (34). In addition, purine pathway intermediates are known to diffuse across cell membranes and might transfer between host cells and A. tumefaciens cells, which raises the possibility that the donor bacteria may also be affected by disruption of purine synthesis in the host cell.…”

Section: Discussionmentioning

confidence: 99%

Purine synthesis and increasedAgrobacterium tumefacienstransformation of yeast and plants

Roberts

Metz

Monks

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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The bacterium Agrobacterium tumefaciens transforms eukaryotic hosts by transferring DNA to the recipient cell where it is integrated and expressed. Bacterial factors involved in this interkingdom gene transfer have been described, but less is known about host-cell factors. Using the yeast Saccharomyces cerevisiae as a model host, we devised a genetic screen to identify yeast mutants with altered transformation sensitivities. Twenty-four adenine auxotrophs were identified that exhibited supersensitivity to A. tumefaciens-mediated transformation when deprived of adenine. We extended these results to plants by showing that purine synthesis inhibitors cause supersensitivity to A. tumefaciens transformation in three plant species. The magnitude of this effect is large and does not depend on prior genetic manipulations of host cells. These data indicate the utility of yeast as a model for the transformation process and identify purine biosynthesis as a key determinant of transformation efficiency. These findings should increase the utility of A. tumefaciens in genetic engineering.A grobacterium tumefaciens, a Gram-negative soil bacterium, genetically transforms plants by transferring DNA to the host cell where it is integrated into the host chromosome and expressed. Exogenous DNA sequences introduced into transferred DNA (T-DNA) vectors can be delivered to plants, making A. tumefaciens a cornerstone of plant genetic engineering. Under controlled conditions, A. tumefaciens can also transform mammalian cells and a variety of fungi, including the yeast Saccharomyces cerevisiae (1-6).Understanding the cellular factors influencing transformation will provide broader insights into the mechanisms underlying interkingdom DNA transfer and should increase the utility of A. tumefaciens in genetic engineering. Bacterial factors that control virulence gene induction as well as processing and delivery of the T-DNA have been studied extensively (7,8). Recently, a few host-cell factors have been identified that participate in A. tumefaciens-mediated transformation. Studies in Arabidopsis thaliana have implicated histone H2A in chromosomal integration of the T-DNA (9). Studies in S. cerevisiae have implicated a nuclear pore protein in T-DNA nuclear import (10) and nonhomologous end-joining proteins in T-DNA chromosomal integration (11). To date, however, the facile yeast system has not been used to perform a large-scale screen to identify host factors that influence transformation sensitivity. Consequently, we devised a genetic screen to isolate yeast mutants with altered sensitivity to A. tumefaciens-mediated transformation. This approach revealed an unexpected link between transformation efficiency and de novo biosynthesis of adenine, an essential purine precursor of DNA, RNA, and ATP. Materials and MethodsStrains and Plasmids. The supervirulent A. tumefaciens strain EHA105 harboring pKP506 served as the bacterial donor strain in yeast-transformation experiments (1). The pKP506 plasmid contains the yeast TRP1 marker and the ARS1 rep...

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“…The pathway begins with glutamine and phosphoribosylpyrophosphate and proceeds through multiple sequential enzymatic steps to the end product inosine monophosphate, which is subsequently used as the precursor for the biosynthesis of other purine nucleotides (1,2). Some bacteria use the nitrogen in purine bases as an energy source under nitrogen-limited conditions.…”

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confidence: 99%

“…Uric acid, a major intermediate of purine catabolism, can be excreted or subjected to further degradation, depending on the presence of unique enzyme systems in different organisms. Sequential enzymatic reactions using uric acid as a substrate result in ureides, including allantoin and allantoate (Scheme 1) (1,3,4). This ureide pathway plays a vital role in transporting and storing the nitrogen fixed in leguminous plants in the form of ureides, which have a relatively high N-to-C ratio of 1.0.…”

mentioning

confidence: 99%

Structural and functional analysis of PucM, a hydrolase in the ureide pathway and a member of the transthyretin-related protein family

Jung

Lee

Park

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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The ureide pathway, which produces ureides from uric acid, is an essential purine catabolic process for storing and transporting the nitrogen fixed in leguminous plants and some bacteria. PucM from Bacillus subtilis was recently characterized and found to catalyze the second reaction of the pathway, hydrolyzing 5-hydroxyisourate (HIU), a product of uricase in the first step. PucM has 121 amino acid residues and shows high sequence similarity to the functionally unrelated protein transthyretin (TTR), a thyroid hormone-binding protein. Therefore, PucM belongs to the TTRrelated proteins (TRP) family. The crystal structures of PucM at 2.0 Å and its complexes with the substrate analogs 8-azaxanthine and 5,6-diaminouracil reveal that even with their overall structure similarity, homotetrameric PucM and TTR are completely different, both in their electrostatic potential and in the size of the active sites located at the dimeric interface. Nevertheless, the absolutely conserved residues across the TRP family, including His-14, Arg-49, His-105, and the C-terminal Tyr-118 -Arg-119 -Gly-120 -Ser-121, indeed form the active site of PucM. Based on the results of sitedirected mutagenesis of these residues, we propose a possible mechanism for HIU hydrolysis. The PucM structure determined for the TRP family leads to the conclusion that diverse members of the TRP family would function similarly to PucM as HIU hydrolase.5-hydroxyisourate hydrolase ͉ Bacillus subtilis ͉ purine catabolism T he purine de novo biosynthesis is the universal, central metabolic process in all organisms. The pathway begins with glutamine and phosphoribosylpyrophosphate and proceeds through multiple sequential enzymatic steps to the end product inosine monophosphate, which is subsequently used as the precursor for the biosynthesis of other purine nucleotides (1, 2). Some bacteria use the nitrogen in purine bases as an energy source under nitrogen-limited conditions. Therefore, the catabolic pathway degrading purine nucleotides has been proposed to be an essential metabolic process (reviewed in refs. 3 and 4). Uric acid, a major intermediate of purine catabolism, can be excreted or subjected to further degradation, depending on the presence of unique enzyme systems in different organisms. Sequential enzymatic reactions using uric acid as a substrate result in ureides, including allantoin and allantoate (Scheme 1) (1,3,4). This ureide pathway plays a vital role in transporting and storing the nitrogen fixed in leguminous plants in the form of ureides, which have a relatively high N-to-C ratio of 1.0. Moreover, symbiotic N 2 -fixing bacteria actively supply the available nitrogen, which is in turn assimilated into glutamine, a substrate in the first step of purine biosynthesis. In the ureide pathway, the conversion of uric acid into allantoin was initially thought to involve a single step catalyzed by urate oxidase (E.C. 1.7.3.3; uricase), but recent investigations have revealed that this pathway includes two additional, distinct, chemically labile intermedi...

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Purine Biosynthesis. Big in Cell Division, Even Bigger in Nitrogen Assimilation

Cited by 192 publications

References 40 publications

National Science Foundation-Sponsored Workshop Report. Draft Plan for Soybean Genomics

National Science Foundation-Sponsored Workshop Report. Draft Plan for Soybean Genomics

Purine synthesis and increasedAgrobacterium tumefacienstransformation of yeast and plants

Structural and functional analysis of PucM, a hydrolase in the ureide pathway and a member of the transthyretin-related protein family

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