title: Direct Measurement of the Nanomechanical Stability of a Redox Protein Active Site and Its Dependence upon Metal Binding.
abstract: The structural basis of the low reorganization energy of cupredoxins has long been debated. These proteins reconcile a conformationally heterogeneous and exposed metal-chelating site with the highly rigid copper center required for efficient electron transfer. Here we combine single-molecule mechanical unfolding experiments with statistical analysis and computer simulations to show that the metal-binding region of apo-azurin is mechanically flexible and that high mechanical stability is imparted by copper binding. The unfolding pathway of the metal site depends on the pulling residue and suggests that partial unfolding of the metal-binding site could be facilitated by the physical interaction with certain regions of the redox protein.
authors: Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) , Madrid 28029, Spain.|Physical Chemistry Department, Universitat de Barcelona , Barcelona 08028, Spain.|Institute for Bioengineering of Catalonia (IBEC) , Baldiri Reixac 15-21, Barcelona 08028, Spain.
authors: Marina I
authors: MI
authors: Giannotti
authors: Joint BSC-CRG-IRB Research Program in Computational Biology, Barcelona Supercomputing Center , Jordi Girona 29, Barcelona 08034, Spain.
authors: Israel
authors: I
authors: Cabeza de Vaca
authors: Physical Chemistry Department, Universitat de Barcelona , Barcelona 08028, Spain.|Institute for Bioengineering of Catalonia (IBEC) , Baldiri Reixac 15-21, Barcelona 08028, Spain.
authors: Juan M
authors: JM
authors: Artés
authors: Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) , Madrid 28029, Spain.|Physical Chemistry Department, Universitat de Barcelona , Barcelona 08028, Spain.|Institute for Bioengineering of Catalonia (IBEC) , Baldiri Reixac 15-21, Barcelona 08028, Spain.
authors: Fausto
authors: F
authors: Sanz
authors: Joint BSC-CRG-IRB Research Program in Computational Biology, Barcelona Supercomputing Center , Jordi Girona 29, Barcelona 08034, Spain.|Catalan Institution for Research and Advanced Studies (ICREA) , Barcelona 08010, Spain.
authors: Victor
authors: V
authors: Guallar
authors: Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) , Madrid 28029, Spain.|Institute for Bioengineering of Catalonia (IBEC) , Baldiri Reixac 15-21, Barcelona 08028, Spain.|Catalan Institution for Research and Advanced Studies (ICREA) , Barcelona 08010, Spain.
authors: Pau
authors: P
authors: Gorostiza
mesh_terms: D001059:Apoproteins / Q000737:chemistry / Q000378:metabolism; D001400:Azurin / Q000737:chemistry* / Q000378:metabolism*; D020134:Catalytic Domain; D003300:Copper / Q000378:metabolism* / Q000494:pharmacology*; D055595:Mechanical Phenomena; D008958:Models, Molecular; D036103:Nanotechnology; D010084:Oxidation-Reduction; D011485:Protein Binding; D011487:Protein Conformation; D055550:Protein Stability / Q000187:drug effects; D058767:Protein Unfolding / Q000187:drug effects; D011550:Pseudomonas aeruginosa
chemical_list: D001059:Apoproteins; D001400:Azurin; D003300:Copper