A number of crystal structures have been solved for this class of enzymes, revealing that they share a common ATP binding domain.
To allow for interaction with this class of enzymes, ATP must first bind to a metal ion such as magnesium or manganese.
This enzyme mechanism is an example of catalysis by approximation: the nucleoside-phosphate kinase binds the substrates to bring them together in the correct position for the phosphoryl group to be transferred.
Similar catalytic domains are present in a variety of proteins, including: When a phylogenetic tree composed of members of the nucleoside-phosphate kinase family was made,[14] it showed that these enzymes had originally diverged from a common ancestor into long and short varieties.
Following the evolution of long and short varieties of NMP-kinases, smaller changes in the amino acid sequences resulted in the differentiation of subcellular localization.