Scheme 3.
Redox-controlled site specific α2–6-sialylation with different sialic acid forms and substrate scope and application of redox-controlled site-specific α2–6-sialylation strategy.a
aReagents and conditions: EM4, one-pot two-enzyme α2–8-sialylation module with NmCSS and CjCstII; EM5, one-pot three-enzyme β1–3-galactosylation module with EcGalK, BLUSP and EcWbgO; EM6, one-pot three-enzyme β1–4-N-acetylgalactosaminylation module with BlNahK, EcGlmU and GalT1 Y289L; EM7, one-pot two-enzyme α2–3-sialylation module with NmCSS and PmST1, see Supporting Information for details.