3BOA: Crystal Structure Of Yeast Protein Disulfide Isomerase

Protein-disulfide isomerase (PDI) catalyzes the formation of the correct pattern of disulfide bonds in secretory proteins. A low resolution crystal structure of yeast PDI described here reveals large scale conformational changes compared with the initially reported structure, indicating that PDI is a highly flexible molecule with its catalytic domains, a and a', representing two mobile arms connected to a more rigid core composed of the b and b' domains. Limited proteolysis revealed that the linker between the a domain and the core is more susceptible to degradation than that connecting the a' domain to the core. By restricting the two arms with inter-domain disulfide bonds, the molecular flexibility of PDI, especially that of its a domain, was demonstrated to be essential for the enzymatic activity in vitro and in vivo. The crystal structure also featured a PDI dimer, and a propensity to dimerize in solution and in the ER was confirmed by cross-linking experiments and the split green fluorescent protein system. Although sedimentation studies suggested that the self-association of PDI is weak, we hypothesize that PDI exists as an interconvertible mixture of monomers and dimers in the endoplasmic reticulum due to its high abundance in this compartment.
PDB ID: 3BOADownload
MMDB ID: 66881
PDB Deposition Date: 2007/12/17
Updated in MMDB: 2008/12
Experimental Method:
x-ray diffraction
Resolution: 3.7  Å
Source Organism:
Similar Structures:
Biological Unit for 3BOA: dimeric; determined by author and by software (PISA)
Molecular Components in 3BOA
Label Count Molecule
Proteins (2 molecules)
Protein Disulfide-isomerase(Gene symbol: PDI1)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB