8RF7

Crystal structure of maize adenosine kinase 2 (ADK2) apoform

8RF7 の概要

• エントリーDOI: 10.2210/pdb8rf7/pdb
• 分子名称: Adenosine kinase, SULFATE ION, ACETATE ION, ... (5 entities in total)
• 機能のキーワード: adenosine kinase, atp, adenosine, cytokinin, transferase
• 由来する生物種: Zea mays
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 78848.31

構造登録者

Morera, S.,Kopecny, D.,Vigouroux, A. (登録日: 2023-12-12, 公開日: 2025-01-01, 最終更新日: 2025-09-03)

主引用文献

Kopecny, D.J.,Vigouroux, A.,Belicek, J.,Kopecna, M.,Koncitikova, R.,Friedecka, J.,Mik, V.,Supikova, K.,Humplik, J.F.,Le Berre, M.,Plancqueel, S.,Strnad, M.,von Schwartzenberg, K.,Novak, O.,Morera, S.,Kopecny, D.
A monomer-dimer switch modulates the activity of plant adenosine kinase.
J.Exp.Bot., 76:3457-3479, 2025

PubMed Abstract: Adenosine undergoes ATP-dependent phosphorylation catalyzed by adenosine kinase (ADK). In plants, ADK also phosphorylates cytokinin ribosides, transport forms of the hormone. Here, we investigated the substrate preferences, oligomeric states, and structures of ADKs from moss (Physcomitrella patens) and maize (Zea mays) alongside metabolomic and phenotypic analyses. We showed that dexamethasone-inducible ZmADK overexpressor lines in Arabidopsis can benefit from a higher number of lateral roots and larger root areas under nitrogen starvation. We discovered that maize and moss enzymes can form dimers upon increasing protein concentration, setting them apart from the monomeric human and protozoal ADKs. Structural and kinetic analyses revealed a catalytically inactive unique dimer. Within the dimer, both active sites are mutually blocked. The activity of moss ADKs, exhibiting a higher propensity to dimerize, was 10-fold lower compared with maize ADKs. Two monomeric structures in a ternary complex highlight the characteristic transition from an open to a closed state upon substrate binding. This suggests that the oligomeric state switch can modulate the activity of moss ADKs and probably other plant ADKs. Moreover, dimer association represents a novel negative feedback mechanism, helping to maintain steady levels of adenosine and AMP.

PubMed: 40063605
DOI: 10.1093/jxb/eraf094

実験手法

X-RAY DIFFRACTION (2.051 Å)