Acetyltransferase that modifies the UDP-4-amino-sugar to form UDP-N,N'-diacetylbacillosamine in the N-linked protein glycosylation pathway. acetyl-CoA + UDP-N-acetylbacillosamine = CoA + H(+) + UDP-N,N'-diacetylbacillosamine kcat is 483000 min(-1) (PubMed:17087520). kcat is 314 sec(-1) (PubMed:18667421). Protein modification; protein glycosylation. Homotrimer. N-linked protein glycosylation in C.jejuni consists in the transfer of a heptasaccharide (GalNAc-alpha1,4-GalNAc-alpha1,4-(Glcbeta1,3)-GalNAc-alpha1,4-GalNAc-alpha1,4-GalNAc-alpha1,3-bacillosamine) from a membrane-anchored undecaprenylpyrophosphate (Und-PP)-linked donor to the Asn side chain of proteins at the Asn-X-Ser/Thr motif. Belongs to the transferase hexapeptide repeat family.