The mechanochemistry of copper reports on the directionality of unfolding in model cupredoxin proteins.

TitleThe mechanochemistry of copper reports on the directionality of unfolding in model cupredoxin proteins.
Publication TypeJournal Article
Year of Publication2015
AuthorsBeedle AEM, Lezamiz A, Stirnemann G, Garcia-Manyes S
JournalNature Comm.
Volume6
Pagination7894
ISBN Numberdoi:10.1038/ncomms8894
ISSN2041-1723
Abstract

Understanding the directionality and sequence of protein unfolding is crucial to elucidate the underlying folding free energy landscape. An extra layer of complexity is added in metalloproteins, where a metal cofactor participates in the correct, functional fold of the protein. However, the precise mechanisms by which organometallic interactions are dynamically broken and reformed on (un)folding are largely unknown. Here we use single molecule force spectroscopy AFM combined with protein engineering and MD simulations to study the individual unfolding pathways of the blue-copper proteins azurin and plastocyanin. Using the nanomechanical properties of the native copper centre as a structurally embedded molecular reporter, we demonstrate that both proteins unfold via two independent, competing pathways. Our results provide experimental evidence of a novel kinetic partitioning scenario whereby the protein can stochastically unfold through two distinct main transition states placed at the N and C termini that dictate the direction in which unfolding occurs.

URLhttp://www.nature.com/ncomms/2015/150803/ncomms8894/abs/ncomms8894.html
DOI10.1038/ncomms8894
Citation Key2015|1729