Fig. 4.
Validation of the pyruvyltransferase activity of WbbZ. WbbY1-722 catalyzes the polymerization of the O1 antigen using compound 1 (shown to the right) as an acceptor, and inclusion of WbbZ results in premature polymerization termination that is dependent on the presence of PEP. WbbYE318A transfers a single β-Galp residue onto 1 resulting in trisaccharide compound 2. Inclusion of WbbZ with WbbYE318A results in a fast-migrating species, consistent with the added charge of pyruvate. The identities of the various compounds were determined by mass spectrometry (SI Appendix, Fig. S4) and NMR spectroscopy (SI Appendix, Fig. S5). Reactions were performed three times with similar results. FL is the fluorescent aglycone.