Structural snapshots along the reaction mechanism of the atypical poplar thioredoxin-like2.1.

Kamel Chibani (1) , Frederick Saul (2) , Claude Didierjean (3) , Nicolas Rouhier (1) , Ahmed Haouz (2)

1 IAM - Interactions Arbres-Microorganismes
2 Cristallographie (Plateforme) - Crystallography (Platform)
3 CRM2 - Cristallographie, Résonance Magnétique et Modélisations

Plastidial thioredoxin (TRX)-like2.1 proteins are atypical thioredoxins possessing a WCRKC active site signature and using glutathione for recycling. To obtain structural information supporting the peculiar catalytic mechanisms and target proteins of these TRXs, we solved the crystal structures of poplar TRX-like2.1 in oxidized and reduced states and of mutated variants. These structures share similar folding with TRXs exhibiting the canonical WCGPC signature. Moreover, the overall conformation is not altered by reduction of the catalytic disulfide bond or in a C45S/C67S variant that formed a disulfide-bridged dimer possibly mimicking reaction intermediates with target proteins. Modeling of the interaction of TRX-like2.1 with both NADPH- and ferredoxin-thioredoxin reductases (FTR) indicates that the presence of Arg43 and Lys44 residues likely precludes reduction by the plastidial FTR.

Mots clés: CHLAMYDOMONAS-REINHARDTII; DITHIOL-DISULFIDE EXCHANGE; ESCHERICHIA-COLI THIOREDOXIN; glutathione; disulfide exchange; crystalline structure; crystal structure; PHOTOSYNTHETIC ORGANISMS; CATALYTIC MECHANISM; REDOX CONTROL; PLANTS; GLUTATHIONYLATION; REDUCTASE; SYSTEMS; atypical thioredoxin; Populus

Mots clés: thioredoxine; glutathion; ferrodoxine; structure cristalline

Domaines: Sciences du Vivant [q-bio]

Kamel Chibani, Frederick Saul, Claude Didierjean, Nicolas Rouhier, Ahmed Haouz. Structural snapshots along the reaction mechanism of the atypical poplar thioredoxin-like2.1.. FEBS Letters, 2018, 592 (6), pp.1030-1041. ⟨10.1002/1873-3468.13009⟩. ⟨hal-01844909⟩