Startseite Linear three-iron centres are unlikely cluster degradation intermediates during unfolding of iron-sulfur proteins
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Linear three-iron centres are unlikely cluster degradation intermediates during unfolding of iron-sulfur proteins

  • Sónia S. Leal und Cláudio M. Gomes
Veröffentlicht/Copyright: 9. Dezember 2005
Biological Chemistry
Aus der Zeitschrift Band 386 Heft 12

Abstract

Recent studies on the chemical alkaline degradation of ferredoxins have contributed to the hypothesis that linear three-iron centres are commonly observed as degradation intermediates of iron-sulfur clusters. In this work we assess the validity of this hypothesis. We studied different proteins containing iron-sulfur clusters, iron-sulfur centres and di-iron centres with respect to their chemical degradation kinetics at high pH, in the presence and absence of exogenous sulfide, to investigate the possible formation of linear three-iron centres during protein unfolding. Our spectroscopic and kinetic data show that in these different proteins visible absorption bands at 530 and 620 nm are formed that are identical to those suggested to arise from linear three-iron centres. Iron release and protein unfolding kinetics show that these bands result from the formation of iron sulfides at pH 10, produced by the degradation of the iron centres, and not from rearrangements leading to linear three-iron centres. Thus, at this point any relevant functional role of linear three-iron centres as cluster degradation intermediates in iron-sulfur proteins remains elusive.

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Published Online: 2005-12-09
Published in Print: 2005-12-01

©2005 by Walter de Gruyter Berlin New York

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