Fig 1: RBD-CD ESI-MS characterization (A) Amino acid sequence of the RBD-CD recombinant protein. The verified sequence by ESI-MS/MS analysis is underlined. The first residues correspond to additional 18 amino acids from the pDisplay subcloning vector. In black the receptor-binding domain (RBD) of SARS-CoV-2 S protein (residues Glu324-Gly535). The lines represent disulfide bonds that link C336-C361, C379-C432, C480-C488, and C391-C525 (for RBD) and C178-C218 for CD154. Residues indicated as N correspond to potential N-glycosylation sites. (B) ESI-MS spectrum of tryptic digestion of the RBD-CD protein in a buffer-free solution. The signals marked with diamonds correspond to the RBD protein peptides, the triangles to the CD154 fragment, and the ovals to the six His tails plus the spacer arm.
Supplier Page from Sino Biological, Inc. for Human CD40 Ligand/CD40L/CD154 Gene ORF cDNA clone expression plasmid, C-His tag