Abstract
The nanATEK-yhcH, yjhATS, and yjhBC operons in Escherichia coli are coregulated by environmental N-acetylneuraminic acid, the most prevalent sialic acid in nature. Here we show that YjhS (NanS) is a probable 9-O-acetyl N-acetylneuraminic acid esterase required for E. coli to grow on this alternative sialic acid, which is commonly found in mammalian host mucosal sites.