Microscopic pKa Values of Escherichia coli Thioredoxin

Chivers, Péter T.; Prehoda, Kenneth E.; Volkman, Brian F.; Kim, Byung-Moon; Markley, John L.; Raines, Ronald T.

doi:10.1021/bi970071j

Cited by 171 publications

(220 citation statements)

References 33 publications

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“…14 The highest value (9.2) is Asp 26 in E. coli thioredoxin, where the side chain is completely buried near the active site. 31,32 Another Asp with a pK value near 9 is the V66D variant of staph nuclease, where the side chain is buried in the hydrophobic core of the protein. 29 In the case of Glu, the lowest value (2.1) is Glu73 in barnase.…”

Section: Resultsmentioning

confidence: 99%

A summary of the measured pK values of the ionizable groups in folded proteins

2008

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We tabulated 541 measured pK values reported in the literature for the Asp, Glu, His, Cys, Tyr, and Lys side chains, and the C and N termini of 78 folded proteins. The majority of these values are for the Asp, Glu, and His side chains. The average pK values are Asp 3.5 6 1.2 (139); Glu 4.2 6 0.9 (153); His 6.6 6 1.0 (131); Cys 6.8 6 2.7 (25); Tyr 10.3 6 1.2 (20); Lys 10.5 6 1.1 (35); Cterminus 3.3 6 0.8 (22) and N-terminus 7.7 6 0.5 (16). We compare these results with the measured pK values of these groups in alanine pentapeptides, and comment on our overall findings.

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Section: Resultsmentioning

confidence: 99%

A summary of the measured pK values of the ionizable groups in folded proteins

2008

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“…However, the pK a value of the N-terminal Cys in the WCPLC motif, which is below 6 corresponds to a value usually observed for an oxidant and not for a disulfide reductant. For instance, the pK a of the corresponding catalytic Cys in E. coli Trx1 is 7.5, whereas it is of 3.5 in the periplasmic oxidase DsbA (25,26). The fact that the apparent second-order rate constant of reduction of the oxidized N-terminal domain by DTT (5.…”

Section: Discussionmentioning

confidence: 99%

The N-terminal Domain of PILB from Neisseria meningitidis Is a Disulfide Reductase That Can Recycle Methionine Sulfoxide Reductases

Wu¹,

Neiers²,

Boschi‐Muller

et al. 2005

Journal of Biological Chemistry

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The PilB protein of the Neisseria genus comprises three domains. Two forms have been recently reported to be produced in vivo. One form, containing the three domains, is secreted from the bacterial cytoplasm to the outer membrane, whereas the second form, which is cytoplasmic, only contains the central and the C-terminal domains. The secreted form was shown to be involved in survival under oxidative conditions. Although previous studies indicated that the central and the Cterminal domains display methionine sulfoxide reductase A and B activities, respectively, no function was described so far for the N-terminal domain. In the present study, the N-terminal domain of the PilB of Neisseria meningitidis was produced as a folded entity, and its biochemical and enzymatic properties have been determined. The data show that the N-terminal domain possesses a disulfide redox-active site with a redox potential in the range of that of thioredoxin. Moreover, the N-terminal domain, either as an isolated form or included in PilB, recycles the oxidized forms of the methionine sulfoxide reductases like thioredoxin. These results, which show that the N-terminal domain exhibits a disulfide reductase activity and probably has a thioredoxin-fold, are discussed in relation to its possible functional role in Neisseria.

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“…All samples containing AdoCbl were kept in black microcentrifuge tubes. E. coli thioredoxin (Trx, 40 units/mg) and thioredoxin reductase (TrxR, 1400 units/mg) were isolated as described previously (38,39). The assay mixture contained in a final volume of 140 l the following: (40).…”

Section: Methodsmentioning

confidence: 99%