4x43

Structure of proline-free E. coli Thioredoxin

spinqualitylabelsall models 4x43, resolution 1.65Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4x43 is a 3 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [THIO_ECOLI] Participates in various redox reactions through the reversible oxidation of its active center dithiol to a disulfide and catalyzes dithiol-disulfide exchange reactions. Publication Abstract from PubMed Cis prolyl peptide bonds are conserved structural elements in numerous protein families, although their formation is energetically unfavorable, intrinsically slow and often rate-limiting for folding. Here we investigate the reasons underlying the conservation of the cis proline that is diagnostic for the fold of thioredoxin-like thiol-disulfide oxidoreductases. We show that replacement of the conserved cis proline in thioredoxin by alanine can accelerate spontaneous folding to the native, thermodynamically most stable state by more than four orders of magnitude. However, the resulting trans alanine bond leads to small structural rearrangements around the active site that impair the function of thioredoxin as catalyst of electron transfer reactions by more than 100-fold. Our data provide evidence for the absence of a strong evolutionary pressure to achieve intrinsically fast folding rates, which is most likely a consequence of proline isomerases and molecular chaperones that guarantee high in vivo folding rates and yields. Acceleration of protein folding by four orders of magnitude through a single amino acid substitution.,Roderer DJ, Scharer MA, Rubini M, Glockshuber R Sci Rep. 2015 Jun 30;5:11840. doi: 10.1038/srep11840. PMID:26121966 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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