Genome Property Definition Page

Nameproposed nine-carbon sugar biosynthesis cassette
DescriptionThe seven genes that form the core of this apparently laterally transferred cassette include four genes homologous to the NeuABCD genes producing acetyl-modified CMP-neuraminic (sialic) acids. This nine-carbon sugar is formed from the condensation of UMP-GlcNAc and phosphoenolpyruvate. In addition to these genes are an epimerase/dehydratase gene distantly similar to 4,6-dehydratases and a aminotransferase distantly similar to perosamine synthetase. It is reasonable to propose that these two genes act on UDP-GlcNAc or a similar sugar to remove the 6-hydroxyl group and replace the 4-hydroxyl group with an amino group, possibly changing the chirality of one or both of those centers in the process. The purpose of the final additional gene in the cassette, a nucleotidyltransferase is unclear, although the production of a bis-nucleotidylsugar, or alternatively, two different nucleotidylsugars are possibilities. In many organisms additional genes are observed intercalated with these seven, suggesting additional modifications to the product such as methyl- and formyl-transferases, redox enzymes, etc.

Step NameStep NumRequiredEvidence (Method)Evidence Go Terms
NeuD-like acetyltransferaseACTYESTIGR03570 (HMM-CLUST): sugar O-acyltransferase, sialic acid O-acetyltransferase NeuD family
epimerase/dehydratase, LLPSF__EDH_00030 familyEDHYESTIGR04180 (HMM): NAD dependent epimerase/dehydratase, LLPSF_EDH_00030 family
cytidylyltransferase, LLPSF_NCT_000029 familyNCT0029YES2810 (RULE_BASE)
aminotransferase, LLPSF_NHT_00031 familyNHTYESTIGR04181 (HMM): aminotransferase, LLPSF_NHT_00031 family