Extensive analysis of different allelelic structures of the chicken BF2 and β2m proteins

No information is available to date on the different allelelic structures of the chicken MHC class I (BF2) and β2m proteins. To elucidate the structure, new allelic β2m and five different BF2 genes were expressed solubly and purified in a pMAL-p2X/E. coli TB1 system. The 2D structure was detected by circular dichroism (CD) spectroscopy, and the 3D structures of their peptide-binding domain (PBD) were analyzed by homology modeling. The sequence lengths of the α-helix, β-sheet, turn, and random coil in the five BF2 proteins were 69–73 aa, 67–72 aa, 35–37 aa, and 94–98 aa, respectively. The new β2m protein displayed a typical β-sheet. Homology modeling of the different BF2 and β2m proteins demonstrated similarities to the structure of human and rat MHC class I proteins. The 3D structure, however, revealed that the BF2 and β2m structures were unique. The correct refolding of recombinant BF2 and β2m proteins might be a powerful tool to further detect antigenic peptides.