Crystal structure of the W35A mutant thioredoxinh fromChlamydomonas reinhardtii: The substitution of the conserved active site Trp leads to modifications in the environment of the two catalytic cysteines

Abstract

The conformational analysis of W35A thioredoxin h from the eukaryotic green alga Chlamydomonas reinhardtii in the solid state has been carried out by x‐ray diffraction, with the aim to clarify the role of Trp in the catalysis. Comparative analysis of W35A mutant with wild‐type (WT) thioredoxin shows that, even if the structural motif of thioredoxin is not perturbed, the substitution of Trp35 by an Ala leads to significant changes in protein conformation near the active site. This rearrangement increases its solvent exposure and explains the change of the pKa values of the catalytic cysteines. The substitution of the Trp residue also influences the crystal packing as well as the recognition ability of thioredoxin. The solid state analysis suggests that the Trp residue has a structural function both to force the active site in the bioactive conformation, and to mediate the protein–protein recognition. © 2001 John Wiley & Sons, Inc. Biopolymers 56: 1–7, 2001

Characterization of a Phanerochaete chrysosporium Glutathione Transferase Reveals a Novel Structural and Functional Class with Ligandin Properties

“…S6). Trp-21 is a very well conserved residue in thioredoxins that is involved in enzyme substrate recognition (49), and Pro-23 is a well conserved residue in the active site motif in the class I glutaredoxins (50).…”

Crystal Structures of a Poplar Thioredoxin Peroxidase that Exhibits the Structure of Glutathione Peroxidases: Insights into Redox-driven Conformational Changes

“…47 Indeed, Menchise et al (2001) suggested that the Trp residue at the active site of TRX has a dual function both to force the active site in the bioactive conformation and to mediate protein-protein recognition. 47 We therefore simulated two model complexes of oPtGPX5-TRX h1. The poplar TRX h1 enzyme exhibits an unusual active site with the sequence WCPPC rather than the typical WCGPC motif.…”

Structure of thioredoxin from Trypanosoma brucei brucei

“…The crystal structures of several thioredoxins have been solved, from E. coli [10,11], human [12], Anabaena [13], Chlamydomonas reinhardtii [14,15] and spinach [16]. In this paper, we report the three‐dimensional structure of T. brucei Trx at 1.4 Å resolution.…”