Details
| Original language | English |
|---|---|
| Pages (from-to) | 734-751 |
| Number of pages | 18 |
| Journal | The plant cell |
| Volume | 31 |
| Issue number | 3 |
| Early online date | 20 Feb 2019 |
| Publication status | Published - Mar 2019 |
Abstract
Plants can fully catabolize purine nucleotides. A firmly established central intermediate is the purine base xanthine. In the current widely accepted model of plant purine nucleotide catabolism, xanthine can be generated in various ways involving either inosine and hypoxanthine or guanosine and xanthosine as intermediates. In a comprehensive mutant analysis involving single and multiple mutants of urate oxidase, xanthine dehydrogenase, nucleoside hydrolases, guanosine deaminase, and hypoxanthine guanine phosphoribosyltransferase, we demonstrate that purine nucleotide catabolism in Arabidopsis (Arabidopsis thaliana) mainly generates xanthosine, but not inosine and hypoxanthine, and that xanthosine is derived from guanosine deamination and a second source, likely xanthosine monophosphate dephosphorylation. Nucleoside hydrolase 1 (NSH1) is known to be essential for xanthosine hydrolysis, but the in vivo function of a second cytosolic nucleoside hydrolase, NSH2, is unclear. We demonstrate that NSH1 activates NSH2 in vitro and in vivo, forming a complex with almost two orders of magnitude higher catalytic efficiency for xanthosine hydrolysis than observed for NSH1 alone. Remarkably, an inactive NSH1 point mutant can activate NSH2 in vivo, fully preventing purine nucleoside accumulation in nsh1 background. Our data lead to an altered model of purine nucleotide catabolism that includes an NSH heterocomplex as a central component.
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)
- Plant Science
- Biochemistry, Genetics and Molecular Biology(all)
- Cell Biology
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In: The plant cell, Vol. 31, No. 3, 03.2019, p. 734-751.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - AMP and GMP Catabolism in Arabidopsis Converge on Xanthosine, Which Is Degraded by a Nucleoside Hydrolase Heterocomplex
AU - Baccolini, Chiara
AU - Witte, Claus-Peter
N1 - Funding Information: We thank André Specht and Hildegard Thölke for technical support, Anting Zhu for generating pXNS2cpmv-Strep (V90), Nieves Medina Escobar for generating pXNS2pat-myc (V103), and Lennart Doering for performing the site-directed mutagenesis of NSH1 and NSH2. We also thank Marc Heins, Sebastian Hoffmann, Sue Genschmer, Manuel Maidorn, Robin Meier, Vincenzo Puggioni, Jana Scharnberg, Anne Taraschewski, and Anting Zhu for generating and screening the double and triple Arabidopsis mutants used in thisstudy.Thisworkwas financiallysupportedbytheDeutscheForschungs-gemeinschaft (grants WI3411/2-1 and WI3411/4-1) and the German Academic Exchange Service (DAAD full PhD fellowship to C.B.).
PY - 2019/3
Y1 - 2019/3
N2 - Plants can fully catabolize purine nucleotides. A firmly established central intermediate is the purine base xanthine. In the current widely accepted model of plant purine nucleotide catabolism, xanthine can be generated in various ways involving either inosine and hypoxanthine or guanosine and xanthosine as intermediates. In a comprehensive mutant analysis involving single and multiple mutants of urate oxidase, xanthine dehydrogenase, nucleoside hydrolases, guanosine deaminase, and hypoxanthine guanine phosphoribosyltransferase, we demonstrate that purine nucleotide catabolism in Arabidopsis (Arabidopsis thaliana) mainly generates xanthosine, but not inosine and hypoxanthine, and that xanthosine is derived from guanosine deamination and a second source, likely xanthosine monophosphate dephosphorylation. Nucleoside hydrolase 1 (NSH1) is known to be essential for xanthosine hydrolysis, but the in vivo function of a second cytosolic nucleoside hydrolase, NSH2, is unclear. We demonstrate that NSH1 activates NSH2 in vitro and in vivo, forming a complex with almost two orders of magnitude higher catalytic efficiency for xanthosine hydrolysis than observed for NSH1 alone. Remarkably, an inactive NSH1 point mutant can activate NSH2 in vivo, fully preventing purine nucleoside accumulation in nsh1 background. Our data lead to an altered model of purine nucleotide catabolism that includes an NSH heterocomplex as a central component.
AB - Plants can fully catabolize purine nucleotides. A firmly established central intermediate is the purine base xanthine. In the current widely accepted model of plant purine nucleotide catabolism, xanthine can be generated in various ways involving either inosine and hypoxanthine or guanosine and xanthosine as intermediates. In a comprehensive mutant analysis involving single and multiple mutants of urate oxidase, xanthine dehydrogenase, nucleoside hydrolases, guanosine deaminase, and hypoxanthine guanine phosphoribosyltransferase, we demonstrate that purine nucleotide catabolism in Arabidopsis (Arabidopsis thaliana) mainly generates xanthosine, but not inosine and hypoxanthine, and that xanthosine is derived from guanosine deamination and a second source, likely xanthosine monophosphate dephosphorylation. Nucleoside hydrolase 1 (NSH1) is known to be essential for xanthosine hydrolysis, but the in vivo function of a second cytosolic nucleoside hydrolase, NSH2, is unclear. We demonstrate that NSH1 activates NSH2 in vitro and in vivo, forming a complex with almost two orders of magnitude higher catalytic efficiency for xanthosine hydrolysis than observed for NSH1 alone. Remarkably, an inactive NSH1 point mutant can activate NSH2 in vivo, fully preventing purine nucleoside accumulation in nsh1 background. Our data lead to an altered model of purine nucleotide catabolism that includes an NSH heterocomplex as a central component.
UR - http://www.scopus.com/inward/record.url?scp=85064975800&partnerID=8YFLogxK
U2 - 10.1105/tpc.18.00899
DO - 10.1105/tpc.18.00899
M3 - Article
VL - 31
SP - 734
EP - 751
JO - The plant cell
JF - The plant cell
SN - 1040-4651
IS - 3
ER -