Effect of divers anions on the electron-transfer reaction between iron and rusticyanin from Thiobacillus ferrooxidans

Rusticyanin is a soluble blue copper protein found in abundance in the periplasmic space of Thiobacillus ferrooxidans, an acidophilic bacterium capable of growing chemolithotrophically on soluble ferrous sulfate. The one-electron-transfer reactions between soluble iron and purified rusticyanin were...

Full description

Saved in:
Bibliographic Details
Published in:Biochemistry (Easton) 1991-10, Vol.30 (39), p.9443-9449
Main Authors: Blake, Robert C, White, Kathy J, Shute, Elizabeth A
Format: Article
Language:English
Subjects:
550200 - Biochemistry
ANIONS
Anions - chemistry
Azurin - analogs & derivatives
Azurin - chemistry
BACILLUS
BACTERIA
Bacterial Proteins - chemistry
BASIC BIOLOGICAL SCIENCES
BIOCHEMICAL REACTION KINETICS
Biological and medical sciences
CHARGED PARTICLES
COPPER COMPOUNDS
COPPER SULFATES
DOSE-RESPONSE RELATIONSHIPS
Electrochemistry
ELECTRON TRANSFER
Fundamental and applied biological sciences. Psychology
IONS
iron
Iron - chemistry
IRON COMPOUNDS
KINETICS
Ligands
METABOLISM
METALLOPROTEINS
MICROORGANISMS
Molecular biophysics
ORGANIC COMPOUNDS
Oxidation-Reduction
OXYGEN COMPOUNDS
Physical chemistry in biology
PROTEINS
REACTION KINETICS
rusticyanin
SULFATES
SULFUR COMPOUNDS
SULFUR-OXIDIZING BACTERIA
Thermodynamics
Thiobacillus - metabolism
THIOBACILLUS FERROXIDANS
TRANSITION ELEMENT COMPOUNDS
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Rusticyanin is a soluble blue copper protein found in abundance in the periplasmic space of Thiobacillus ferrooxidans, an acidophilic bacterium capable of growing chemolithotrophically on soluble ferrous sulfate. The one-electron-transfer reactions between soluble iron and purified rusticyanin were studied by stopped-flow spectrophotometry in acidic solutions containing each of 14 different anions. The second-order rate constants for both the Fe(II)-dependent reduction and the Fe(III)-dependent oxidation of the rusticyanin varied as a function of the identity of the principal anion in solution. Analogous electron-transfer reactions between soluble iron and bis(dipicolinato)cobaltate(III) or bis(dipicolinato)ferrate(II) were studied by stopped-flow spectrophotometry under solution conditions identical with those of the rusticyanin experiments. Similar anion-dependent reactivity patterns were obtained with soluble iron whether the other reaction partner was rusticyanin or either of the two organometallic complexes. The Marcus theory of outer-sphere electron transfer reactions was applied to this set of kinetic data to demonstrate that the rusticyanin may possess at least two electron-transfer pathways for liganded iron, one where the pattern of electron-transfer reactivity is controlled largely by protein-independent activation parameters and one where the protein exhibits an anion-dependent kinetic specificity. The exact role of rusticyanin in the iron-dependent respiratory electron transport chain of T. ferrooxidans remains unclear.
ISSN:0006-2960
1520-4995
DOI:10.1021/bi00103a008