CMP-N,N'-diacetyllegionaminic acid synthase (, CMP-N,N'-diacetyllegionaminic acid synthetase, neuA (gene), legF (gene)) is an enzyme with systematic name CTP:N,N'-diacetyllegionaminate cytidylyltransferase. This enzyme catalyses the following chemical reaction
This enzyme is isolated from the bacteria Legionella pneumophila and Campylobacter jejuni.