Related Experiment Video
Updated: May 7, 2026

Author Spotlight: In Silico Creation and Impact of Carbonylated Amino Acids on Protein Structure and Function
Published on: April 26, 2024
A novel twist on molecular interactions between thioredoxin and nicotinamide adenine dinucleotide phosphate-dependent
Kristine G Kirkensgaard1, Per Hägglund, Azar Shahpiri
1Enzyme and Protein Chemistry Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark; The Protein Chemistry Group, Carlsberg Laboratory, DK-1799 København V, Denmark.
Abstract:
The ubiquitous disulfide reductase thioredoxin (Trx) regulates several important biological processes such as seed germination in plants. Oxidized cytosolic Trx is regenerated by nicotinamide adenine dinucleotide phosphate (NADPH)-dependent thioredoxin reductase (NTR) in a multistep transfer of reducing equivalents from NADPH to Trx via a tightly NTR-bound flavin. Here, interactions between NTR and Trx are predicted by molecular modelling of the barley NTR:Trx complex (HvNTR2:HvTrxh2) and probed by site directed mutagenesis. Enzyme kinetics analysis reveals mutants in a loop of the flavin adenine dinucleotide (FAD)-binding domain of HvNTR2 to strongly affect the interaction with Trx. In particular, Trp42 and Met43 play key roles for recognition of the endogenous HvTrxh2. Trx from Arabidopsis thaliana is also efficiently recycled by HvNTR2 but turnover in this case appears to be less dependent on these two residues, suggesting a distinct mode for NTR:Trx recognition. Comparison between the HvNTR2:HvTrxh2 model and the crystal structure of the Escherichia coli NTR:Trx complex reveals major differences in interactions involving the FAD- and NADPH-binding domains as supported by our experiments. Overall, the findings suggest that NTR:Trx interactions in different biological systems are fine-tuned by multiple intermolecular contacts.
More Related Videos
08:23Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds
Published on: February 16, 2022
07:24Paramagnetic Relaxation Enhancement for Detecting and Characterizing Self-Associations of Intrinsically Disordered Proteins
Published on: September 23, 2021
Related Concept Videos
Redox Reactions
Redox Reactions
Role of Reduced Coenzymes NADH and FADH₂
Oxidation and Reduction of Organic Molecules
The removal of an electron from a molecule, results in a...
Electron Transport Chain: Complex I and II
ROS generation is regulated and maintained at moderate levels necessary...
Riboswitches
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...