INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
artículos
Título:
A spectroscopic study of the temperature induced modifications on ferredoxin folding and iron-sulfur moieties
Autor/es:
TODOROVIC S (TODOROVIC, SMIJA), LEAL SS (LEAL, SONIA S.), SALGUEIRO CA (SALGUEIRO, CARLOS A.), ZEBGER I (ZEBGER, INGO), HILDEBRANDT P (HILDEBRANDT, PETER), MURGIDA DH (MURGIDA, DANIEL H.), GOMES CM (GOMES, CLAUDIO M.)
Revista:
BIOCHEMISTRY
Referencias:
Año: 2007 vol. 46 p. 10733 - 10738
ISSN:
0006-2960
Resumen:
Thermal perturbation of the dicluster ferredoxin from Acidianus
ambivalens was investigated employing a toolbox of spectroscopic
methods. FTIR and visible CD were used for assessing changes of the
secondary structure and coarse alterations of the [3Fe4S] and [4Fe4S]
cluster moieties, respectively. Fine details of the disassembly of the
metal centers were revealed by paramagnetic NMR and resonance Raman
spectroscopy. Overall, thermally induced unfolding of AaFd is initiated
with the loss of alpha-helical content at relatively low temperatures
(T-m(app) similar to 44 degrees C, followed by the disruption of both
iron-sulfur clusters (T-m(app) similar to 53-60 degrees C. The
degradation of the metal centers triggers major structural changes on
the protein matrix, including the loss of tertiary contacts (T-m(app)
similar to 58 degrees C) and a change, rather than a significant net
loss, of secondary structure (T-m(app) similar to 60 degrees C. This
latter process triggers a secondary structure reorganization that is
consistent with the formation of a molten globule state. The combined
spectroscopic approach here reported illustrates how changes in the
metalloprotein organization are intertwined with disassembly of the
iron-sulfur centers, denoting the conformational interplay of the
protein backbone with cofactors.