Identifying Sequential Substrate Binding at the Single-Molecule Level by Enzyme Mechanical StabilizationReport as inadecuate




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Resumen

Enzyme-substrate binding is a dynamic process intimately coupled to protein structural changes, which in turn changes the unfolding energy landscape. By the use of single-molecule force spectroscopy SMFS, we characterize the open-to-closed conformational transition experienced by the hyperthermophilic adenine diphosphate ADP-dependent glucokinase from Thermococcus litoralis triggered by the sequential binding of substrates. In the absence of substrates, the mechanical unfolding of TIGK shows an intermediate 1, which is stabilized in the presence of Mg center dot ADP-, the first substrate to bind to the enzyme. However, in the presence of this substrate, an additional unfolding event is observed, intermediate 1*. Finally, in the presence of both substrates, the unfolding force of intermediates 1 and 1* increases as a consequence of the domain closure. These results show that SMFS can be used as a powerful experimental tool to investigate binding mechanisms of different enzymes with more than one ligand, expanding the repertoire of protocols traditionally used in enzymology.Nota general

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Author: Rivas Pardo, Jaime; - Alegre Cebollada, Jorge; - Ramírez Sarmiento, César; - Fernández, Julio M.; - Guixé Leguía, Victoria;

Source: http://repositorio.uchile.cl/



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