The Acid-Base Properties, Hydrolytic Mechanism, and Susceptibility to O(2) Oxidation of Fe(4)S(4)(SR)(4) Clusters.

Proceedings of the National Academy of Sciences of the United States of America ·Vol. 72 ·No. 1 ·1975-01-00 ·Pages 231-4

Bruice TC, Maskiewicz R, Job R

Abstract

The iron-sulfur cluster compounds Fe(4)S(4)(SR)(4) (-2) [where -SR = -SCH(3), -S-C(CH(3))(3), and -S- CH(2)-CH(CH(3))(2)] have been found to represent the base species of weak acids of pK(a) comparable to that of carboxylic acids. The acid species Fe(4)S(4)(SR)(4)H(-) is most subject to reaction with O(2) and to acid-catalyzed solvolysis, while the base species Fe(4)S(4)(SR)(4) (-2) most readily undergoes ligand exchange. The kinetics for hydrolysis of the isobutyl mercaptide cluster salt has been investigated in detail and a mechanism involving the stepwise process [Formula: see text] has been proposed. The importance of the acid-base equilibria in determining the reactivity of the iron-sulfur clusters and its possible importance as a factor in the determination of the potentials of ferredoxins and high potential iron protein are discussed.

Authors & Affiliations

3 authors, click to expand affiliations / ORCID

Bruice T C

Department of Chemistry, University of California, Santa Barbara, Calif. 93106.

Maskiewicz R

Job R

References (11)

11 references, click to expand

"Super-reduction" of chromatium high-potential iron-sulphur protein in the presence of dimethyl sulphoxide.
Biochem Biophys Res Commun. 1973 Sep 18;54(2):548-54 PMID: 4356972
The electron paramagnetic resonance of oxidized clostridial ferredoxins.
Biochem Biophys Res Commun. 1974 Jul 10;59(1):188-94 PMID: 4366753
Structure and properties of a synthetic analogue of bacterial iron--sulfur proteins.
Proc Natl Acad Sci U S A. 1972 Sep;69(9):2437-41 PMID: 4506765
On pig heart aconitase.
Biochem Biophys Res Commun. 1972 May 26;47(4):740-5 PMID: 5026292
Synthetic analogs of the active sites of iron-sulfur proteins. VII. Ligand substitution reactions of the tetranuclear clusters (Fe4S4(SR)4)2- and the structure of ((CH3)4N)2(Fe4S4(SC6H5)4).
J Am Chem Soc. 1974 Jun 26;96(13):4168-78 PMID: 4854592
Synthetic analogs of the active sites of iron-sulfur proteins. VI. Spectral and redox characteristics of the tetranuclear clusters (Fe4S4(SR)4).2-.
J Am Chem Soc. 1974 Jun 26;96(13):4159-67 PMID: 4854591
Equivalence of metal centers in the iron-sulfur protein active site analogs (Fe4S4(SR)4)2-.
J Am Chem Soc. 1974 Apr 17;96(8):2644-6 PMID: 4833717
Synthetic analogs of the active sites of iron-sulfur proteins. V. Proton resonance properties of the tetranuclear clusters (Fe4S4(SR)4). Evidence for dominant contact interactions.
J Am Chem Soc. 1974 Apr 3;96(7):2109-17 PMID: 4833642
Synthetic analogs of the active sites of iron-sulfur proteins. II. Synthesis and structure of the tetra(mercapto-m 3 -sulfido-iron) clusters, (Fe 4 S 4 (SR) 4 ) 2- .
J Am Chem Soc. 1973 May 30;95(11):3523-34 PMID: 4708377
Iron-sulfur proteins: structure and function.
Annu Rev Biochem. 1973;42(0):159-204 PMID: 4599384
A comparison of Fe 4 S 4 clusters in high-potential iron protein and in ferredoxin.
Proc Natl Acad Sci U S A. 1972 Dec;69(12):3526-9 PMID: 4509310

Article Info

Journal

Proceedings of the National Academy of Sciences of the United States of America

Abbr.

Proc Natl Acad Sci U S A

ISSN

0027-8424

DOI

10.1073/pnas.72.1.231

Published

1975-01-00

Pages

231-4

Language

English

Region

United States

NLM ID

7505876

PMCID

PMC432277

External Links

PubMed source DOI: 10.1073/pnas.72.1.231 PMC Full Text View journal details

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The Acid-Base Properties, Hydrolytic Mechanism, and Susceptibility to O(2) Oxidation of Fe(4)S(4)(SR)(4) Clusters.

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