NDLI: Studies on the degradation pathway of iron-sulfur centers during unfolding of a hyperstable ferredoxin: cluster dissociation, iron release and protein stability

Content Provider	Springer Nature Link
Author	Leal, Sónia S. Teixeira, Miguel Gomes, Cláudio M.
Copyright Year	2004
Abstract	The ferredoxin from the thermoacidophile Acidianus ambivalens is a representative of the archaeal family of di-cluster [3Fe-4S][4Fe-4S] ferredoxins. Previous studies have shown that these ferredoxins are intrinsically very stable and led to the suggestion that upon protein unfolding the iron-sulfur clusters degraded via linear three-iron sulfur center species, with 610 and 520 nm absorption bands, resembling those observed in purple aconitase. In this work, a kinetic and spectroscopic investigation on the alkaline chemical denaturation of the protein was performed in an attempt to elucidate the degradation pathway of the iron-sulfur centers in respect to protein unfolding events. For this purpose we investigated cluster dissociation, iron release and protein unfolding by complementary biophysical techniques. We found that shortly after initial protein unfolding, iron release proceeds monophasically at a rate comparable to that of cluster degradation, and that no typical EPR features of linear three-iron sulfur centers are observed. Further, it was observed that EDTA prevents formation of the transient bands and that sulfide significantly enhances its intensity and lifetime, even after protein unfolding. Altogether, our data suggest that iron sulfides, which are formed from the release of iron and sulfide resulting from cluster degradation during protein unfolding in alkaline conditions, are in fact responsible for the observed intermediate spectral species, thus disproving the hypothesis suggesting the presence of a linear three-iron center intermediate. Kinetic studies monitored by visible, fluorescence and UV second-derivative spectroscopies have elicited that upon initial perturbation of the tertiary structure the iron-sulfur centers start decomposing and that the presence of EDTA accelerates the process. Also, the presence of EDTA lowers the observed melting temperature in thermal ramp experiments and the midpoint denaturant concentration in equilibrium chemical unfolding experiments, further suggesting that the clusters also play a structural role in the maintenance of the conformation of the folded state.
Starting Page	987
Ending Page	996
Page Count	10
File Format	PDF
ISSN	09498257
Journal	JBIC Journal of Biological Inorganic Chemistry
Volume Number	9
Issue Number	8
e-ISSN	14321327
Language	English
Publisher	Springer-Verlag
Publisher Date	2004-10-02
Publisher Place	Berlin, Heidelberg
Access Restriction	One Nation One Subscription (ONOS)
Subject Keyword	Iron-sulfur centers Kinetics Protein folding Stability Thermophiles
Content Type	Text
Resource Type	Article
Subject	Biochemistry Inorganic Chemistry

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

Iron–sulfur protein folds, iron–sulfur chemistry, and evolution

Combined spectroscopic and calorimetric characterisation of rubredoxin reversible thermal transition

Pro108 is important for folding and stabilization of adrenal ferredoxin, but does not influence the functional properties of the protein.

Role of a novel disulfide bridge within the all-beta fold of soluble Rieske proteins

Formation of a linear [3Fe-4S] cluster in a seven-iron ferredoxin triggered by polypeptide unfolding

Spectroscopic studies of the tungsten-containing formaldehyde ferredoxin oxidoreductase from the hyperthermophilic archaeon Thermococcus litoralis

Iron–sulfur cluster exchange reactions mediated by the human Nfu protein

Mechanisms of iron–sulfur cluster assembly: the SUF machinery

A substrate channel in the nitrogenase MoFe protein

Studies on the degradation pathway of iron-sulfur centers during unfolding of a hyperstable ferredoxin: cluster dissociation, iron release and protein stability

Similar Documents

Iron–sulfur protein folds, iron–sulfur chemistry, and evolution

Combined spectroscopic and calorimetric characterisation of rubredoxin reversible thermal transition

Pro108 is important for folding and stabilization of adrenal ferredoxin, but does not influence the functional properties of the protein.

Role of a novel disulfide bridge within the all-beta fold of soluble Rieske proteins

Formation of a linear [3Fe-4S] cluster in a seven-iron ferredoxin triggered by polypeptide unfolding

Spectroscopic studies of the tungsten-containing formaldehyde ferredoxin oxidoreductase from the hyperthermophilic archaeon Thermococcus litoralis

Iron–sulfur cluster exchange reactions mediated by the human Nfu protein

Mechanisms of iron–sulfur cluster assembly: the SUF machinery

A substrate channel in the nitrogenase MoFe protein

Studies on the degradation pathway of iron-sulfur centers during unfolding of a hyperstable ferredoxin: cluster dissociation, iron release and protein stability