Dissecting the functional roles of the conserved NXXE and HXE motifs of the ADP-dependent glucokinase from Thermococcus litoralisReport as inadecuate




Dissecting the functional roles of the conserved NXXE and HXE motifs of the ADP-dependent glucokinase from Thermococcus litoralis - Download this document for free, or read online. Document in PDF available to download.

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The activity of the ADP-dependent glucokinase from Thermococcus litoralis TlGK relies on thehighly conserved motifs NXXE i.e. Asn-Xaa-Xaa-Glu and HXE i.e. His-Xaa-Glu. Site-directed mutagenesisof residues Glu279 HXE and Glu308 NXXE leads to enzymes with highly reduced catalyticrates. The replacement of Glu308 by Gln increased the KM for MgADP and was activated by freeMg2+. On the other hand, HXE mutants did not affect the KM for MgADP , were still inhibited by freeMg2+, and caused a large increase on KM for glucose and an 87-fold weaker binding of glucose ontothe non-hydrolysable TlGK AMP–AlF3 complex. Our findings put forward the fundamental role ofthe HXE motif in glucose binding during ternary complex formationNota general

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Author: Abarca Lagunas, María José; - Rivas Pardo, Jaime; - Ramírez Sarmiento, César; - Giuxé Leguia, Victoria; -

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



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