Broad-specificity nucleoside monophosphate (NMP) kinase that catalyzes the reversible transfer of the terminal phosphate group between nucleoside triphosphates and monophosphates. Preferred phosphate donor and acceptor are ATP and AMP, respectively. Has also ATPase activity (By similarity). AMP + ATP = 2 ADP Interacts with RPS14A. Decreased stem growth. Belongs to the adenylate kinase family. AK6 subfamily.