Sialoglycoconjugates present in vertebrates are linked exclusively by α-linkages and are released in α form during degradation. This enzyme accelerates maturotation to the β form (which also occurs as a slow spontaneous reaction), which is necessary for further metabolism by the bacteria.
Severi, E., Müller, A., Potts, J.R., Leech, A., Williamson, D., Wilson, K.S. and Thomas, G.H. Sialic acid mutarotation is catalyzed by the Escherichia coli β-propeller protein YjhT. J. Biol. Chem.283 (2008) 4841–4849. [PMID: 18063573]