Screening of peptides binding to NTCP

We developed a human cell surface display strategy to screen peptides binding to the HBV receptor NTCTP based on preS1-21. PeS1-21 was extended by 7 random amino acids, and fused with mCherry and FasL transmembrane domain. The pooled constructs were transfected into HEK293 cells by using the transposon/transposase system to create a library displaying various peptides on the cell surface with red fluorescence. On the other hand, we expressed NTCP protein fused with EGFP on HEK293 and used the membrane lysate containing NTCP-GFP as bait protein to select peptides with increased NTCP affinity. After certain cycles of selection, deep sequencing was used to analyze the polypeptides that were enriched.