The redox properties of protein disulfide isomerase (DsbA) of Escherichia coli result from a tense conformation of its oxidized form.


Abstract

Periplasmic protein disulfide isomerase (DsbA) from Escherichia coli is a strongly oxidizing thiol reagent with one catalytic disulfide bridge and an intrinsic redox potential of -0.089 V. Gel filtration experiments and analytical ultracentrifugation studies demonstrate that DsbA is a monomeric protein with a molecular mass of 21.1 kDa, independent of its redox state. In order to investigate the molecular basis of its redox properties, the guanidinium.chloride-induced folding/unfolding equilibrium of the reduced and the oxidized form of the enzyme were compared. The transitions at pH 7.0 and 30 degrees C were found to be fully reversible and allowed the calculation of the free energy of stabilization of oxidized and reduced DsbA according to a two-state model for the unfolding transition. The analysis reveals that reduced DsbA is 22.7 (+/- 4.0) kJ/mol more stable than oxidized DsbA. This energetic difference is essentially independent of temperature, although the overall free energies of stabilization of both oxidized and reduced DsbA vary strongly between 20 and 30 degrees C as a consequence of changes in the cooperativity of the transitions The conformational tension of 22.7 (+/- 4.0) kJ/mol in oxidized DsbA quantitatively explains the oxidizing properties of the protein, as it causes a change of redox equilibrium constants between DsbA and thiols of about four orders of magnitude, corresponding to an increase of the standard redox potential of 0.118 (+/- 0.021) V. We conclude that the oxidizing properties of DsbA mainly result from a tense conformation of its oxidized form, that is converted to the relaxed, reduced state upon oxidation of thiols by DsbA. The results are discussed in terms of a general principle underlying the oxidizing properties of protein disulfide isomerases. Study holds ProTherm entries: 9268, 9269, 9270, 9271 Extra Details: additive : EDTA(50 uM), DsbA protein; protein disulfide isomerase (PDI);,protein folding; redox potential

Submission Details

ID: tczyqmXJ3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:37 p.m.

Version: 1

Publication Details
Wunderlich M;Jaenicke R;Glockshuber R,J. Mol. Biol. (1993) The redox properties of protein disulfide isomerase (DsbA) of Escherichia coli result from a tense conformation of its oxidized form. PMID:8411164
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P
 

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)


Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
3DKS 2008-06-25T00:00:00+0000 1.9 DsbA substrate complex
1A23 1998-01-15T00:00:00+0000 0 SOLUTION NMR STRUCTURE OF REDUCED DSBA FROM ESCHERICHIA COLI, MINIMIZED AVERAGE STRUCTURE
1A24 1998-01-15T00:00:00+0000 0 SOLUTION NMR STRUCTURE OF REDUCED DSBA FROM ESCHERICHIA COLI, FAMILY OF 20 STRUCTURES
1A2J 1998-01-06T00:00:00+0000 2.0 OXIDIZED DSBA CRYSTAL FORM II
1A2L 1998-01-06T00:00:00+0000 2.7 REDUCED DSBA AT 2.7 ANGSTROMS RESOLUTION
1A2M 1998-01-06T00:00:00+0000 2.7 OXIDIZED DSBA AT 2.7 ANGSTROMS RESOLUTION, CRYSTAL FORM III
1AC1 1997-02-10T00:00:00+0000 2.0 DSBA MUTANT H32L
1ACV 1997-02-10T00:00:00+0000 1.9 DSBA MUTANT H32S
1BQ7 1998-08-21T00:00:00+0000 2.8 DSBA MUTANT P151A, ROLE OF THE CIS-PROLINE IN THE ACTIVE SITE OF DSBA
1DSB 1993-05-24T00:00:00+0000 2.0 CRYSTAL STRUCTURE OF THE DSBA PROTEIN REQUIRED FOR DISULPHIDE BOND FORMATION IN VIVO

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
99.5 Thiol:disulfide interchange protein DsbA P52235 DSBA_SHIFL
99.5 Thiol:disulfide interchange protein DsbA P0A4L5 DSBA_ECOL6
99.5 Thiol:disulfide interchange protein DsbA P0A4L6 DSBA_ECO27
100.0 Thiol:disulfide interchange protein DsbA P0AEG4 DSBA_ECOLI
100.0 Thiol:disulfide interchange protein DsbA P0AEG5 DSBA_ECO57