Fig. 9.

Rendering of the structure (Protein Data Bank, PDB ID: 1LDS) of B2M showing the site of the native disulfide, and of GAPDH (PDB ID: 1J0X) showing the sites of the free Cys residues. Panel A: The intra-disulfide (Cys25-Cys80) in B2M is shown as a van der Waals spheres representation: with the red colored atom being the sulfur atom of Cys25, and the green colored atom the sulfur atom of Cys80. Panel B: the Cys25-Cys80 disulfide in B2M is shown as a ball and stick representation and indicates the buried location of this species within the protein structure. Panel C: localization of the sulfur atoms of the free Cys residues in GAPDH: red colored atom - Cys149; blue colored atom - Cys153; green colored atom - Cys244; yellow colored atom - Cys281. Cys149 and Cys244 were identified as residues involved in the observed inter-protein disulfides between B2M and GAPDH, with Cys149 being highly exposed on the protein surface as indicated by the bright color of parts of this amino acid in the rendering of the protein structure. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)