Growth-regulating oxygenase that catalyzes the hydroxylation of 50S ribosomal protein L16 on 'Arg-81'. 2-oxoglutarate + L-arginyl-[ribosomal protein uL16] + O2 = (3R)-3-hydroxy-L-arginyl-[ribosomal protein uL16] + CO2 + succinate Binds 1 Fe(2+) ion per subunit. Homodimer. Cells lacking this gene grow similarly as wild-type under standard conditions, but show reduced growth under low nutrient conditions; this result correlates with a bulk protein translation rate that is lower by a factor of three or four in the deletion mutant strain than that in the wild-type. Deletion of this gene also leads to loss of Rpl16 hydroxylation. Belongs to the ROX family. RoxA/YcfD subfamily.