Crystal structure of fully oxidized human thioredoxin.
Hwang, J., Nguyen, L.T., Jeon, Y.H., Lee, C.Y., Kim, M.H.(2015) Biochem Biophys Res Commun 467: 218-222
- PubMed: 26453009 
- DOI: https://doi.org/10.1016/j.bbrc.2015.10.003
- Primary Citation of Related Structures:  
5DQY - PubMed Abstract: 
In addition to the active cysteines located at positions 32 and 35 in humans, mammalian cytosolic thioredoxin (TRX) possesses additional conserved cysteine residues at positions 62, 69, and 73. These non-canonical cysteine residues, that are distinct from prokaryotic TRX and also not found in mammalian mitochondrial TRX, have been implicated in biological functions regulating signal transduction pathways via their post-translational modifications. Here, we describe for the first time the structure of a fully oxidized TRX. The structure shows a non-active Cys62-Cys69 disulfide bond in addition to the active Cys32-Cys35 disulfide. The non-active disulfide switches the α3-helix of TRX, composed of residues Cys62 to Glu70, to a bulging loop and dramatically changes the environment of the TRX residues involved in the interaction with its reductase and other cellular substrates. This structural modification may have implications for a number of potential functions of TRX including the regulation of redox-dependent signaling pathways.
Organizational Affiliation: 
Infection and Immunity Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, South Korea.