Protein disulfide isomerase
| Protein disulfide-isomerase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC number | 5.3.4.1 | ||||||||
| CAS number | 37318-49-3 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / EGO | ||||||||
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| Search | |
|---|---|
| PMC | articles |
| PubMed | articles |
| NCBI | proteins |
| protein disulfide isomerase family A, member 2 | |
|---|---|
| Identifiers | |
| Symbol | PDIA2 |
| Alt. symbols | PDIP |
| Entrez | 64714 |
| HUGO | 14180 |
| OMIM | 608012 |
| RefSeq | NM_006849 |
| UniProt | Q13087 |
| Other data | |
| Locus | Chr. 16 p13.3 |
| protein disulfide isomerase family A, member 3 | |
|---|---|
| Identifiers | |
| Symbol | PDIA3 |
| Alt. symbols | GRP58 |
| Entrez | 2923 |
| HUGO | 4606 |
| OMIM | 602046 |
| RefSeq | NM_005313 |
| UniProt | P30101 |
| Other data | |
| Locus | Chr. 15 q15 |
| protein disulfide isomerase family A, member 4 | |
|---|---|
| Identifiers | |
| Symbol | PDIA4 |
| Entrez | 9601 |
| HUGO | 30167 |
| RefSeq | NM_004911 |
| UniProt | P13667 |
| Other data | |
| Locus | Chr. 7 q35 |
| protein disulfide isomerase family A, member 5 | |
|---|---|
| Identifiers | |
| Symbol | PDIA5 |
| Entrez | 10954 |
| HUGO | 24811 |
| RefSeq | NM_006810 |
| UniProt | Q14554 |
| Other data | |
| EC number | 5.3.4.1 |
| Locus | Chr. 3 q21.1 |
| protein disulfide isomerase family A, member 6 | |
|---|---|
| Identifiers | |
| Symbol | PDIA6 |
| Alt. symbols | TXNDC7 |
| Entrez | 10130 |
| HUGO | 30168 |
| RefSeq | NM_005742 |
| UniProt | Q15084 |
| Other data | |
| Locus | Chr. 2 p25.1 |
Protein disulfide isomerase or PDI is an enzyme in the endoplasmic reticulum in eukaryotes and the periplasm of bacteria that catalyzes the formation and breakage of disulfide bonds between cysteine residues within proteins as they fold. This allows proteins to quickly find the correct arrangement of disulfide bonds in their fully folded state, and therefore the enzyme acts to catalyze protein folding.
PDI contains four thioredoxin-like domains, two of which retain the canonical CXXC motif. The reduced (dithiol) form of PDI is able to catalyse a reduction of mispaired thiol residues of a particular substrate, acting as an isomerase. Therefore, PDI is capable of catalyzing the post-translational modification disulfide exchange. Such exchange reactions can occur intramolecularly, leading to the rearrangement of disulfide bonds in a single protein.
Another major function of PDI relates to its activity as a chaperone; i.e., it aids wrongly folded proteins to reach a correctly folded state without the aid of enzymatic disulfide shuffling.
Oxidized PDI can catalyze the formation of a disulfide bridge. This reduces PDI, which is re-oxidized by a protein called Ero1.
In the chloroplasts of the unicellular algae Chlamydomonas reinhardtii the PDI RB60 serves as a redox sensor component of an mRNA-binding protein complex implicated in the photo-regulation of the translation of psbA, the RNA encoding for the photosystem II core protein D1. PDI has also been suggested to play a role in the formation of regulatory disulfide bonds in chloroplasts.
PDI helps load antigenic peptides into MHC class I molecules. These molecules (MHC I) are related to the peptide presentation by antigen-presenting cells in the immune response.
PDI has been found to be involved in the breaking of bonds on the HIV gp120 protein during HIV infection of CD4 positive cells, and is required for HIV infection of lymphocytes and monocytes. Some studies have shown it to be available for HIV infection on the surface of the cell clustered around the CD4 protein. Yet conflicting studies have shown that it is not available on the cell surface, but instead is found in significant amounts in the blood plasma.
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Wikipedia