2H4E: Crystal Structure Of Cys10 Sulfonated Transthyretin

Transthyretin (TTR) is a plasma protein, which under conditions not yet completely understood, aggregates forming amyloid deposits that occur extracellularly. It is a protein composed of four identical subunits. Each monomer has a single cysteine residue (Cys10), which in the plasma is reduced (Cys-SH), oxidized (Cys-SO3-), sulfonated (Cys-S-SO3-) or bound to various sulfhydryls. There is evidence that these chemical modifications of the SH group alter the stability and the amyloidogenic potential of the protein. The sulfonated form was found to enhance the stability of the native conformation of TTR, avoiding misassembly of the protein leading to amyloid. Consequently, the potential treatment of TTR-type amyloidosis by sulfite has been suggested. The structure of TTR pre-incubated with sulfite at physiological pH, was determined by X-ray crystallography to provide structural insight for the stabilizing effect of sulfite. Each subunit has a beta-sandwich conformation, with two four stranded beta-pleated sheets (DAGH and CBEF) and a small alpha-helix between strands. The sulfonated cysteines have two sulfite oxygens involved in intramonomer hydrogen bonds that bridge Cys10, the amino acid immediately before beta-strand A, to the amino acids immediately after the edge beta-strand D. Implications of the newly observed interactions in the inhibition of fibril formation are discussed in light of the recent structural models of TTR amyloid fibrils.
PDB ID: 2H4EDownload
MMDB ID: 43843
PDB Deposition Date: 2006/5/24
Updated in MMDB: 2007/11
Experimental Method:
x-ray diffraction
Resolution: 1.45  Å
Source Organism:
Similar Structures:
Biological Unit for 2H4E: tetrameric; determined by author and by software (PISA,PQS)
Molecular Components in 2H4E
Label Count Molecule
Proteins (4 molecules)
Transthyretin(Gene symbol: TTR)
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB