Nov, 2019
Calcium sensing via EF-hand 4 enables thioredoxin activity in the sensor-responder protein calredoxin in the green alga Chlamydomonas reinhardtii.
The Journal of biological chemistry
- Volume
- 295
- Number
- 1
- First page
- 170
- Last page
- 180
- Language
- English
- Publishing type
- Research paper (scientific journal)
- DOI
- 10.1074/jbc.RA119.008735
Calcium (Ca2+) and redox signaling enable cells to quickly adapt to changing environments. The signaling protein calredoxin (CRX) from the green alga Chlamydomonas reinhardtii is a chloroplast-resident thioredoxin having Ca2+-dependent activity and harboring a unique combination of an EF-hand domain connected to a typical thioredoxin-fold. Using small-angle X-ray scattering (SAXS), FRET, and NMR techniques, we found that Ca2+-binding not only induces a conformational change in the EF-hand domain, but also in the thioredoxin domain, translating into the onset of thioredoxin redox activity. Functional analyses of CRX with genetically altered EF-hands revealed that EF-hand 4 is important for mediating the communication between the two domains. Moreover, we crystallized a variant (C174S) of the CRX target protein peroxiredoxin 1 (PRX1) at 2.4 Å resolution, modeled the interaction complex of the two proteins, and analyzed it by cross-linking and MS analyses, revealing that the interaction interface is located close to the active sites of both proteins. Our findings shed light on the Ca2+ binding-induced changes in CRX structure in solution at the level of the overall protein and individual domains and residues.
- Link information
- ID information
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- DOI : 10.1074/jbc.RA119.008735
- ISSN : 0021-9258
- Pubmed ID : 31776187
- Pubmed Central ID : PMC6952598