Download MendeleyLoop Electrostatics Asymmetry Modulates the Preexisting Conformational Equilibrium in Thrombin.
Pozzi, N., Zerbetto, M., Acquasaliente, L., Tescari, S., Frezzato, D., Polimeno, A., Gohara, D.W., Di Cera, E., De Filippis, V.(2016) Biochemistry 55: 3984-3994
- PubMed: 27347732
- DOI: https://doi.org/10.1021/acs.biochem.6b00385
- Primary Citation of Related Structures:
5JDU - PubMed Abstract:
Thrombin exists as an ensemble of active (E) and inactive (E*) conformations that differ in their accessibility to the active site. Here we show that redistribution of the E*-E equilibrium can be achieved by perturbing the electrostatic properties of the enzyme. Removal of the negative charge of the catalytic Asp102 or Asp189 in the primary specificity site destabilizes the E form and causes a shift in the 215-217 segment that compromises substrate entrance. Solution studies and existing structures of D102N document stabilization of the E* form. A new high-resolution structure of D189A also reveals the mutant in the collapsed E* form. These findings establish a new paradigm for the control of the E*-E equilibrium in the trypsin fold.
Organizational Affiliation:
Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine , St. Louis, Missouri 63104, United States.
