Dissecting the functional roles of the conserved NXXE and HXE motifs of the ADP-dependent glucokinase fromThermococcus litoralis
| Autor: | Victoria Guixé, Jaime Andrés Rivas-Pardo, César A. Ramírez-Sarmiento, María José Abarca-Lagunas |
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| Rok vydání: | 2015 |
| Předmět: |
Models
Molecular Archaeal Proteins Amino Acid Motifs Biophysics Protein–ligand binding Biochemistry Conserved sequence chemistry.chemical_compound Structural Biology Catalytic Domain Glucokinase Genetics Thermococcus litoralis Molecular Biology Ternary complex Conserved Sequence Divalent metal cation biology Archaeal enzyme Cell Biology biology.organism_classification Thermococcus Glucose binding Kinetics Glucose Glucose 6-phosphate chemistry ADP-dependent kinase Mutagenesis Site-Directed Adenosine triphosphate |
| Zdroj: | Febs Letters Artículos CONICYT CONICYT Chile instacron:CONICYT |
| ISSN: | 0014-5793 |
| DOI: | 10.1016/j.febslet.2015.09.013 |
| Popis: | The activity of the ADP-dependent glucokinase from Thermococcus litoralis (TlGK) relies on the highly conserved motifs NXXE (i.e. Asn-Xaa-Xaa-Glu) and HXE (i.e. His-Xaa-Glu). Site-directed mutagenesis of residues Glu279 (HXE) and Glu308 (NXXE) leads to enzymes with highly reduced catalytic rates. The replacement of Glu308 by Gln increased the KM for MgADP(-) and was activated by free Mg(2+). On the other hand, HXE mutants did not affect the KM for MgADP(-), were still inhibited by free Mg(2+), and caused a large increase on KM for glucose and an 87-fold weaker binding of glucose onto the non-hydrolysable TlGK·AMP-AlF3 complex. Our findings put forward the fundamental role of the HXE motif in glucose binding during ternary complex formation. |
| Databáze: | OpenAIRE |
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