Redesigning allosteric activation in an enzyme
Research article published in Proceedings of the National Academy of Sciences of the United States of America (2011)
Abstract
Enzyme activation by monovalent cations is widely documented in plants and the animal world. In type II enzymes, activation entails two steps: binding of the monovalent cation to its allosteric site and transduction of this event into enhanced catalytic activity. The effect has exquisite specificity for either Na(+) or K(+), the most abundant cations present in physiological environments. Enzymes requiring K(+) such as kinases and molecular chaperones are not activated as well or at all by the larger cation Cs(+) or the smaller cations Na(+) and Li(+). Enzymes requiring Na(+) such as β-galactosidase and clotting proteases are not activated as well by Li(+), or the larger cations K(+), Rb(+), and Cs(+). Efforts to switch specificity between Na(+) and K(+) in this large class of enzymes and completely redesign the mechanism of allosteric transduction leading to enhanced catalytic activity have so far been unsuccessful. Here we show how mutagenesis of two loops defining the Na(+) binding site of thrombin, a Na(+)-activated clotting protease, generates a construct that is most active in the presence of K(+) toward synthetic and physiological substrates. The effect is the result of a higher binding affinity and more efficient allosteric transduction of binding into enhanced catalytic activity for K(+) compared to Na(+), which represents a complete reversal of the properties of wild type. In addition, the construct features altered specificity toward physiological substrates resulting in a significant anticoagulant profile. The findings are relevant to all Na(+)-activated proteases involved in blood coagulation and the complement system.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
Enzyme activation by monovalent cations is widely documented in plants and the animal world.
Por qué esto importa para la hirudoterapia
Este estudio investigó la activación alostérica de la trombina, una proteasa de coagulación activada por Na+, demostrando cómo la mutagénesis de dos bucles que definen el sitio de unión a Na+ genera una construcción que se activa preferentemente por K+ en lugar de por Na+. La construcción exhibe una especificidad alterada hacia sustratos fisiológicos, dando lugar a un perfil anticoagulante significativo y representando una inversión completa de las propiedades del tipo silvestre, con hallazgos relevantes para las proteasas activadas por Na+ implicadas en la coagulación sanguínea y en el sistema del complemento. El resumen no aporta datos sobre sanguijuelas, hirudoterapia, hirudina ni sobre ningún componente del secretoma de la sanguijuela. Por lo tanto, este artículo no presenta una relevancia aparente para la Sociedad Americana de Hirudoterapia ni para las aplicaciones terapéuticas de la terapia con sanguijuelas.
Citación
Redesigning allosteric activation in an enzyme
Rana S et al. · Proceedings of the National Academy of Sciences of the United States of America, 2011
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Añadido a la biblioteca ASH: May 27, 2026 · Última actualización del sitio: 18 de junio de 2026