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Characterization of Escherichia Coli Thioredoxin Variants Mimicking the Active-sites of Other Thiol/disulfide Oxidoreductases

Overview
Journal Protein Sci
Specialty Biochemistry
Date 1998 May 30
PMID 9605329
Citations 56
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Abstract

Thiol/disulfide oxidoreductases like thioredoxin, glutaredoxin, DsbA, or protein disulfide isomerase (PDI) share the thioredoxin fold and a catalytic disulfide bond with the sequence Cys-Xaa-Xaa-Cys (Xaa corresponds to any amino acid). Despite their structural similarities, the enzymes have very different redox properties, which is reflected by a 100,000-fold difference in the equilibrium constant (K(eq)) with glutathione between the most oxidizing member, DsbA, and the most reducing member, thioredoxin. Here we present a systematic study on a series of variants of thioredoxin from Escherichia coli, in which the Xaa-Xaa dipeptide was exchanged by that of glutaredoxin, PDI, and DsbA. Like the corresponding natural enzymes, all thioredoxin variants proved to be stronger oxidants than the wild-type, with the order wild-type < PDI-type < DsbA-type < glutaredoxin-type. The most oxidizing, glutaredoxin-like variant has a 420-fold decreased value of K(eq), corresponding to an increase in redox potential by 75 mV. While oxidized wild-type thioredoxin is more stable than the reduced form (delta deltaG(ox/red) = 16.9 kJ/mol), both redox forms have almost the same stability in the variants. The pH-dependence of the reactivity with the alkylating agent iodoacetamide proved to be the best method to determine the pKa value of thioredoxin's nucleophilic active-site thiol (Cys32). A pKa of 7.1 was measured for Cys32 in the reduced wild-type. All variants showed a lowered pKa of Cys32, with the lowest value of 5.9 for the glutaredoxin-like variant. A correlation of redox potential and the Cys32 pKa value could be established on a quantitative level. However, the predicted correlation between the measured delta deltaG(ox/red) values and Cys32 pKa values was only qualitative.

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References
1.
Bachmann B . Pedigrees of some mutant strains of Escherichia coli K-12. Bacteriol Rev. 1972; 36(4):525-57. PMC: 408331. DOI: 10.1128/br.36.4.525-557.1972. View

2.
Kallis G, Holmgren A . Differential reactivity of the functional sulfhydryl groups of cysteine-32 and cysteine-35 present in the reduced form of thioredoxin from Escherichia coli. J Biol Chem. 1980; 255(21):10261-5. View

3.
Pace C . Determination and analysis of urea and guanidine hydrochloride denaturation curves. Methods Enzymol. 1986; 131:266-80. DOI: 10.1016/0076-6879(86)31045-0. View

4.
Studier F, Moffatt B . Use of bacteriophage T7 RNA polymerase to direct selective high-level expression of cloned genes. J Mol Biol. 1986; 189(1):113-30. DOI: 10.1016/0022-2836(86)90385-2. View

5.
Kunkel T, Roberts J, Zakour R . Rapid and efficient site-specific mutagenesis without phenotypic selection. Methods Enzymol. 1987; 154:367-82. DOI: 10.1016/0076-6879(87)54085-x. View