Function
Chaperone for NapA, the catalytic subunit of the periplasmic nitrate reductase. It binds directly and specifically to the twin-arginine signal peptide of NapA, preventing premature interaction with the Tat translocase and premature export (PubMed:17901208, PubMed:22329966). May have a role in the insertion of the NapA molybdenum cofactor (PubMed:24314029).