7C65

Crystal structure of thioredoxin m1

Summary for 7C65

• Entry DOI: 10.2210/pdb7c65/pdb
• Descriptor: Thioredoxin M1, chloroplastic, SODIUM ION (3 entities in total)
• Functional Keywords: trx m1, electron transport
• Biological source: Arabidopsis thaliana (Mouse-ear cress)
• Total number of polymer chains: 1
• Total formula weight: 12018.62

Authors

Kurisu, G.,Juniar, L.,Tanaka, H. (deposition date: 2020-05-21, release date: 2020-10-14, Last modification date: 2023-11-29)

Primary citation

Juniar, L.,Tanaka, H.,Yoshida, K.,Hisabori, T.,Kurisu, G.
Structural basis for thioredoxin isoform-based fine-tuning of ferredoxin-thioredoxin reductase activity.
Protein Sci., 29:2538-2545, 2020

PubMed Abstract: Photosynthetic electron transport occurs on the thylakoid membrane of chloroplasts. Ferredoxin (Fd), the final acceptor in the electron transport chain, distributes electrons to several Fd-dependent enzymes including Fd-thioredoxin reductase (FTR). A cascade from Fd to FTR further reduces Thioredoxin (Trx), which tunes the activity of target metabolic enzymes eventually in a light-dependent manner. We previously reported that 10 Trx isoforms in Arabidopsis thaliana can be clustered into three classes based on the kinetics of the FTR-dependent reduction (high-, middle-, and low-efficiency classes). In this study, we determined the X-ray structure of three electron transfer complexes of FTR and Trx isoform, Trx-y1, Trx-f2, and Trx-m2, as representative examples of each class. Superposition of the FTR structure with/without Trx showed no main chain structural changes upon complex formation. There was no significant conformational change for single and complexed Trx-m structures. Nonetheless, the interface of FTR:Trx complexes displayed significant variation. Comparative analysis of the three structures showed two types of intermolecular interactions; (i) common interactions shared by all three complexes and (ii) isoform-specific interactions, which might be important for fine-tuning FTR:Trx activity. Differential electrostatic potentials of Trx isoforms may be key to isoform-specific interactions.

PubMed: 33015914
DOI: 10.1002/pro.3964

Experimental method

X-RAY DIFFRACTION (1.1 Å)