4MNN: The Crystal Structure Of Sso1120 From Sulfolobus Solfataricus

Protein disulfide oxidoreductases (PDOs) are proteins involved in disulfide bond formation playing a crucial role in adaptation to extreme environment. This paper reports the functional and structural characterization of Sso1120, a PDO from the hyperthermophilic archaeon Sulfolobus solfataricus. The protein was expressed in Escherichia coli and purified to homogeneity. The functional characterization showed that the enzyme has reductase activity, as tested by insulin assay, but differently from the other PDOs, it does not present isomerase activity. In addition it is able to form a redox couple with the thioredoxin reductase that could be used in undiscovered pathways. The protein revealed a melting point of around 90 degrees C in CD spectroscopy-monitored thermal denaturation and high denaturant resistance. The X-ray crystallographic structure was solved at 1.80 A resolution, showing differences with respect to other PDOs and an unexpected similarity with the N-terminal domain of the alkyl hydroperoxide reductase F component from Salmonella typhimurium. On the basis of the reported data and of bioinformatics and phylogenetic analyses, a possible involvement of this atypical PDO in a new antioxidant system of S. solfataricus has been proposed.
PDB ID: 4MNNDownload
MMDB ID: 116394
PDB Deposition Date: 2013/9/11
Updated in MMDB: 2014/03
Experimental Method:
x-ray diffraction
Resolution: 1.8  Å
Source Organism:
Similar Structures:
Biological Unit for 4MNN: monomeric; determined by author
Molecular Components in 4MNN
Label Count Molecule
Protein (1 molecule)
Glutaredoxin Related Protein
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

Citing MMDB