"histidine--tRNA ligase"
"histidine--trna ligase"
tRNA(His) + L-histidine + ATP = L-histidyl-tRNA(His) + AMP + diphosphate + H(+)
trna(his) + l-histidine + atp = l-histidyl-trna(his) + amp + diphosphate + h(+)