Structural basis of nectin-1 recognition by pseudorabies virus glycoprotein D
(A) A schematic picture of PRV gD. The boundaries of the domain elements, including the signal peptide (SP), the ectodomain, the transmembrane domain (TM), and the cytoplasmic domain (CP), were determined by bioinformatic predictions using the SignalP4.1 and TMHMM web-server. For recombinant expression of PRV gD in insect cells, the protein was truncated (aa 1–337 for gD337 and aa 1–284 for gD284), engineered with a GP67 signal peptide for secretion, and added with a C-terminal 6His tag for purification. (B) Representative size-exclusion chromatographs of gD337 and gD284. The recombinant PRV gD proteins were purified from the supernatants of the baculovirus-infected insect cells, analyzed on a Hiload 16/60 Superdex 200 column (GE), and then examined by electrophoresis by SDS-PAGE. The resultant separation profiles are shown. (C) An SPR assay characterizing the PRV-gD/nectin-1 binding kinetics. Gradient concentrations of gD337 or gD284 were flow through SW- and HU-nectin-1 immobilized on the chip surface. The real-time binding profiles are recorded and shown.