4KPO

Plant nucleoside hydrolase - ZmNRh3 enzyme

4KPO の概要

• エントリーDOI: 10.2210/pdb4kpo/pdb
• 関連するPDBエントリー: 4KPN
• 分子名称: Nucleoside N-ribohydrolase 3, CALCIUM ION (3 entities in total)
• 機能のキーワード: iu-nrhs, hydrolase
• 由来する生物種: Zea mays (maize)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 71661.79

構造登録者

Morera, S.,Vigouroux, A.,Kopecny, D. (登録日: 2013-05-14, 公開日: 2013-11-27, 最終更新日: 2023-09-20)

主引用文献

Kopecna, M.,Blaschke, H.,Kopecny, D.,Vigouroux, A.,Koncitikova, R.,Novak, O.,Kotland, O.,Strnad, M.,Morera, S.,von Schwartzenberg, K.
Structure and Function of Nucleoside Hydrolases from Physcomitrella patens and Maize Catalyzing the Hydrolysis of Purine, Pyrimidine, and Cytokinin Ribosides.
Plant Physiol., 163:1568-1583, 2013

PubMed Abstract: We present a comprehensive characterization of the nucleoside N-ribohydrolase (NRH) family in two model plants, Physcomitrella patens (PpNRH) and maize (Zea mays; ZmNRH), using in vitro and in planta approaches. We identified two NRH subclasses in the plant kingdom; one preferentially targets the purine ribosides inosine and xanthosine, while the other is more active toward uridine and xanthosine. Both subclasses can hydrolyze plant hormones such as cytokinin ribosides. We also solved the crystal structures of two purine NRHs, PpNRH1 and ZmNRH3. Structural analyses, site-directed mutagenesis experiments, and phylogenetic studies were conducted to identify the residues responsible for the observed differences in substrate specificity between the NRH isoforms. The presence of a tyrosine at position 249 (PpNRH1 numbering) confers high hydrolase activity for purine ribosides, while an aspartate residue in this position confers high activity for uridine. Bud formation is delayed by knocking out single NRH genes in P. patens, and under conditions of nitrogen shortage, PpNRH1-deficient plants cannot salvage adenosine-bound nitrogen. All PpNRH knockout plants display elevated levels of certain purine and pyrimidine ribosides and cytokinins that reflect the substrate preferences of the knocked out enzymes. NRH enzymes thus have functions in cytokinin conversion and activation as well as in purine and pyrimidine metabolism.

PubMed: 24170203
DOI: 10.1104/pp.113.228775

実験手法

X-RAY DIFFRACTION (2.49 Å)