Data from: A monomer-dimer switch modulates the activity of plant adenosine kinase

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 tenfold lower compared to 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
likely other plant ADKs. Moreover, dimer association represents a novel
negative feedback mechanism, helping to maintain steady levels of
adenosine and AMP.