Dr. Peter L. Davies, Queen's University, Department of Biochemistry
Queen's University Peter L. Davies
Professor of Biochemistry & Biology
  • Calpains: calcium-dependent cysteine proteases
  • Calpains are complex, multi-domain proteases involved in calcium signaling in the cell. We are interested in the mechanism by which these enzymes sense calcium and become activated to make specific cuts in target proteins. In addition to the ubiquitous m- and mu-calpain isoforms, a dozen tissue-specific variants have been recognized, all of which share a similar papain-like protease core.<more>

    Conformational change in the protease core of calpain during activation by calcium. (3.3 Mb)
    The active site cleft is realigned by the cooperative binding of two calcium ions (gold spheres) (Moldoveanu et al., 2002). The realignment is shown by the morphing of ten images and appears as a rotation of domain II (left) relative to domain I (right).
    Courtesy of Dr. Rob Campbell
  • Antifreeze Proteins (AFPs)
  • Antifreeze proteins have been isolated from a number of different organisms including fish, insects, plants and bacteria. These proteins are thought to depress the freezing point of solutions by binding to the surface of ice crystals and inhibiting their growth.

    Our lab is currently carrying out structure/function analyses on various AFPs to study how these structurally unrelated proteins serve the same function. <more>

    Tenebrio molitor AFP

    [click on structure for enlargement, 93Kb]
    Structure of beetle (Tenebrio molitor) AFP determined by X-ray crystallography. This is the type of AFP found in a beetle larvae.
    Refer to: Liou, Y.-C., Tocilj, A., Davies, P.L. and Jia, Z. Mimicry of ice structure by surface hydroxyls and water of a ß-helix antifreeze protein (2000) Nature 406, 322-324.
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