SearchPublisher and Institutes
You are here: Home :: Area NEM :: Life sciences :: Biochemistry
Sónia S. Leal, Cláudio M. Gomes
Linear three-iron centres are unlikely cluster degradation intermediates during unfolding of iron-sulfur proteins
Keywords: aconitase, ferredoxin, hydrogenase, iron-sulfur, linear three-iron centres, protein folding
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.
Biological Chemistry, Walter de Gruyter
Print ISSN: 1431-6730
Volume: 386, 12/2005
Pages: 1295 - 1300