Structural architecture of prothrombin in solution revealed by single molecule spectroscopy [electronic resource].
- Washington, D.C. : United States. Dept. of Energy. Office of Basic Energy Sciences ; Oak Ridge, Tenn. : distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2016
- Physical description
- 1 online resource (p. 18107-18116) : digital, PDF file.
- Argonne National Laboratory. Researcher
- United States. Dept. of Energy. Office of Basic Energy Sciences. Sponsor
- United States. Dept. of Energy. Office of Scientific and Technical Information. Distributor
- Nicola Pozzi Author
- Dominika Bystranowska Author
- Xiaobing Zuo Author
- Enrico Di Cera Author
- The coagulation factor prothrombin has a complex spatial organization of its modular assembly that comprises the N-terminal Gla domain, kringle-1, kringle-2, and the C-terminal protease domain connected by three intervening linkers. Here we use single molecule Förster resonance energy transfer to access the conformational landscape of prothrombin in solution and uncover structural features of functional significance that extend recent x-ray crystallographic analysis. Prothrombin exists in equilibrium between two alternative conformations, open and closed. The closed conformation predominates (70%) and features an unanticipated intramolecular collapse of Tyr<sup>93</sup> in kringle-1 onto Trp<sup>547</sup> in the protease domain that obliterates access to the active site and protects the zymogen from autoproteolytic conversion to thrombin. The open conformation (30%) is more susceptible to chymotrypsin digestion and autoactivation, and features a shape consistent with recent x-ray crystal structures. Small angle x-ray scattering measurements of prothrombin wild type stabilized 70% in the closed conformation and of the mutant Y93A stabilized 80% in the open conformation directly document two envelopes that differ 50 Å in length. These findings reveal important new details on the conformational plasticity of prothrombin in solution and the drastic structural difference between its alternative conformations. Prothrombin uses the intramolecular collapse of kringle-1 onto the active site in the closed form to prevent autoactivation. As a result, the open-closed equilibrium also defines a new structural framework for the mechanism of activation of prothrombin by prothrombinase.
- Publication date
- Published through SciTech Connect.
- Journal of Biological Chemistry 291 35 ISSN 0021-9258 AM
- Nicola Pozzi; Dominika Bystranowska; Xiaobing Zuo; Enrico Di Cera.
- Funding Information