Sialic acid O-acyltransferase NeuD-like (IPR020019)

Short name: Sia_OAcTrfase_NeuD-like

Overlapping homologous superfamilies

Family relationships



This entry includes a group of acetyltransferases, such as NeuD sialic acid O-acetyltransferase enzymes from Escherichia coli and Streptococcus agalactiae (group B strep) [PMID: 7814319, PMID: 16490781, PMID: 16923886], UDP-N-acetylbacillosamine N-acetyltransferase pglD from Campylobacter jejuni subsp. jejuni [PMID: 17087520, PMID: 19448740] and GDP-perosamine N-acetyltransferase perB from Escherichia coli O157:H7 [PMID: 18201574]. This group is composed of mostly uncharacterized proteins containing an N-terminal helical subdomain followed by a LbH domain. The alignment contains 6 turns, each containing three imperfect tandem repeats of a hexapeptide repeat motif (X-[STAV].-X-[LIV]-[GAED]-X). Proteins containing hexapeptide repeats are often enzymes showing acyltransferase activity [PMID: 15500694].

The neuD gene is often observed in close proximity to the neuABC genes for the biosynthesis of CMP-N-acetylneuraminic acid (CMP-sialic acid), and NeuD sequences from these organisms were used to construct the seed for this model. Nevertheless, there are numerous instances of sequences identified by this model which are observed in a different genomic context (although almost universally in exopolysaccharide biosynthesis-related loci), as well as in genomes for which the biosynthesis of sialic acid (SA) has not been demonstrated. Even in the cases where the association with SA biosynthesis is strong, it is unclear in the literature whether the biological substrate is SA itself, CMP-SA, or a polymer containing SA. Similarly, it is unclear to what extent the enzyme has a preference for acetylation at the 7, 8 or 9 positions. In the absence of evidence of association with SA, members of this family may be involved with the acetylation of differing sugar substrates, or possibly the delivery of alternative acyl groups. The closest related sequences to this family (and those used to root the phylogenetic tree constructed to create this model) are believed to be succinyltransferases involved in lysine biosynthesis.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.