Download MendeleyNa(+) binding to meizothrombin desF1.
Papaconstantinou, M.E., Gandhi, P.S., Chen, Z., Bah, A., Di Cera, E.(2008) Cell Mol Life Sci 65: 3688-3697
- PubMed: 18854941
- DOI: https://doi.org/10.1007/s00018-008-8502-7
- Primary Citation of Related Structures:
3E6P - PubMed Abstract:
Meizothrombin is the physiologically active intermediate generated by a single cleavage of prothrombin at R320 to separate the A and B chains. Recent evidence has suggested that meizothrombin, like thrombin, is a Na(+)-activated enzyme. In this study we present the first X-ray crystal structure of human meizothrombin desF1 solved in the presence of the active site inhibitor PPACK at 2.1 A resolution. The structure reveals a Na(+) binding site whose architecture is practically identical to that of human thrombin. Stopped-flow measurements of Na(+) binding to meizothrombin desF1 document a slow phase of fluorescence change with a k(obs) decreasing hyperbolically with increasing [Na(+)], consistent with the existence of three conformations in equilibrium, E*, E and E:Na(+), as for human thrombin. Evidence that meizothrombin exists in multiple conformations provides valuable new information for studies of the mechanism of prothrombin activation.
Organizational Affiliation:
Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
