title: Reversible unfolding-refolding of rubredoxin: a single-molecule force spectroscopy study.
abstract: In metalloproteins, metal centers serve as active sites for a range of functional purposes and as important structural elements to facilitate protein folding and assembly. It is challenging to observe the reversible unfolding and refolding of metalloproteins because of a loss or decomposition of the metal center. Here, the reversible unfolding-refolding of the iron-sulfur protein rubredoxin was observed directly using single-molecule force spectroscopy. The results demonstrate that the iron can remain attached to the CXXC motif when rubredoxin is unfolded. Upon relaxation, the unfolded rubredoxin can refold into its native holo state with the reconstituted FeS4 center. The possible loss of iron from the unfolded protein prevents rubredoxin from refolding into its native holo state. These results demonstrated that unfolding of rubredoxin is reversible, as long as the iron remains attached, and provide experimental evidence for the iron-priming mechanism for the folding of rubredoxin.
authors.affiliation: Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1 (Canada); Program in cellular and molecular medicine, Boston Children's Hospital and Department of Biological Chemistry and Molecular Medicine, Harvard Medical School, Boston, MA, 02115 (USA).
authors.forename: Peng
authors.initials: P
authors.lastname: Zheng
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Wang
authors.forename: Hongbin
authors.initials: H
authors.lastname: Li
mesh_terms: D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D058849:Protein Refolding; D058767:Protein Unfolding; D012416:Rubredoxins / Q000737:chemistry*
chemical_list: D012416:Rubredoxins
keywords: force spectroscopy; iron priming; metalloproteins; protein folding; single-molecule studies