The adaptability of Escherichia coli thioredoxin to the substitution of a series of non-natural amino acids has been investigated. Different thiosulfonated alkyl groups were inserted into the hydrophobic core of the protein in position 78 via disulfide bonding with a buried cysteine residue as previously described (Wynn R, Richards FM. 1993. Unnatural amino acid packing mutants of Escherichia coli thioredoxin produced by combined mutagenesis/chemical modification techniques. Protein Sci 2:395-403). The side chains added to the cysteine included methyl, ethyl, n-propyl, n-butyl, n-pentyl, and cyclo-pentyl derivatives. The side chains appear to exploit the presence of the large cavities to incorporate these variant forms, enabling the protein to fold and have some activity. Solution structural and kinetic data suggested that these substitutions had little effect on the overall fold of the protein. Thermodynamic data revealed that the entropic effect of restricting the side chains in the folded protein has an effect on the stability. The variant forms of thioredoxin have different propensities to form dimers despite the limited structural perturbations. Molecular modeling studies allow the conformation of the side chains to be assessed. Study holds ProTherm entries: 9392, 9393, 9394, 9395, 9396, 9397, 9398, 9399, 9400, 9401, 9402, 9403, 9404, 9405, 9406, 9407, 9408, 9409, 9410, 9411, 9412 Extra Details: calorimetry; cysteine modification; differential scanning; kinetics; protein folding; thermodynamics: thioredoxin; unnatural amino acids
ID: kHz5G3mZ3
Submitter: Connie Wang
Submission Date: April 24, 2018, 8:38 p.m.
Version: 1
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Structure ID | Release Date | Resolution | Structure Title |
---|---|---|---|
3DXB | 2008-07-24T00:00:00+0000 | 2.2 | Structure of the UHM domain of Puf60 fused to thioredoxin |
5E4W | 2015-10-07T00:00:00+0000 | 2.8 | Crystal structure of cpSRP43 chromodomains 2 and 3 in complex with the Alb3 tail |
5IKN | 2016-03-03T00:00:00+0000 | 4.8 | Crystal Structure of the T7 Replisome in the Absence of DNA |
1F6M | 2000-06-22T00:00:00+0000 | 2.95 | CRYSTAL STRUCTURE OF A COMPLEX BETWEEN THIOREDOXIN REDUCTASE, THIOREDOXIN, AND THE NADP+ ANALOG, AADP+ |
1KEB | 2001-11-15T00:00:00+0000 | 1.8 | Crystal Structure of Double Mutant M37L,P40S E.coli Thioredoxin |
1M7T | 2002-07-22T00:00:00+0000 | 0 | Solution Structure and Dynamics of the Human-Escherichia coli Thioredoxin Chimera: Insights into Thermodynamic Stability |
1OAZ | 2003-01-21T00:00:00+0000 | 2.78 | IgE Fv SPE7 complexed with a recombinant thioredoxin |
1SKR | 2004-03-05T00:00:00+0000 | 2.4 | T7 DNA Polymerase Complexed To DNA Primer/Template and ddATP |
1SKS | 2004-03-05T00:00:00+0000 | 2.3 | Binary 3' complex of T7 DNA polymerase with a DNA primer/template containing a cis-syn thymine dimer on the template |
1SKW | 2004-03-05T00:00:00+0000 | 2.3 | Binary 3' complex of T7 DNA polymerase with a DNA primer/template containing a disordered cis-syn thymine dimer on the template |