Uncharacterized bacterial proteins with similarity to Aminoglycoside 3'-phosphotransferase and Choline kinase
This subfamily is composed of uncharacterized bacterial proteins with similarity to APH and ChoK. Other APH/ChoK-like proteins include ethanolamine kinase (ETNK), macrolide 2'-phosphotransferase (MPH2'), an unusual homoserine kinase, and uncharacterized proteins with similarity to the N-terminal domain of acyl-CoA dehydrogenase 10 (ACAD10). These proteins catalyze the transfer of the gamma-phosphoryl group from ATP (or CTP) to small molecule substrates, such as aminoglycosides, macrolides, choline, ethanolamine, and homoserine. Phosphorylation of the antibiotics, aminoglycosides, and macrolides leads to their inactivation and to bacterial antibiotic resistance. Phosphorylation of choline, ethanolamine, and homoserine serves as precursors to the synthesis of important biological compounds, such as the major phospholipids, phosphatidylcholine and phosphatidylethanolamine and the amino acids, threonine, methionine, and isoleucine. The APH/ChoK-like subfamily is part of a larger superfamily that includes the catalytic domains of other kinases, such as the typical serine/threonine/tyrosine protein kinases (PKs), RIO kinases, actin-fragmin kinase (AFK), and phosphoinositide 3-kinase (PI3K).