Synthetic assembly of novel avidin-biotin-GlcNAc (ABG) complex as an attractive bio-probe and its interaction with wheat germ agglutinin (WGA)

• GlcNAc, biotin, and avidin were used for this study.
• GlcNAc derivatization gave GlcNAc-biotin conjugate.
• Tetrameric avidin-biotin-GlcNAc (ABG complex) was accomplished by known avidin-biotin interaction.
• Fluorometric assay of the ABG complex against WGA lectin gave high association constant due to the glycocluster effect.

A tetravalent GlcNAc pendant glycocluster was constructed with terminal biotin through C6 linker. To acquire the multivalent carbohydrate-protein interactions, we synthesized a glycopolymer of tetrameric structure using N-acetyl-d-glucosamine (GlcNAc) as the target carbohydrate by the use of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) as coupling reagent, followed by biotin-avidin complexation leading to the formation of glycocluster of avidin-biotin-GlcNAc conjugate (ABG complex). The dynamic light scattering (DLS) system was implied for size detection and to check the binding affinity of GlcNAc conjugate with a WGA lectin we use fluorometric assay by means of specific excitation of tryptophan at λex 295 nm and it was found to be very high Ka ∼ 1.39 × 107 M−1 in case of ABG complex as compared to GlcNAc only Ka ∼ 1.01 × 104 M−1 with the phenomenon proven to be due to glycocluster effect.

Figure optionsDownload as PowerPoint slide