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Steven Smith

  NMR Spectroscopy of Proteins

  Contact Information:  
  Assistant Professor of Biochemistry
B.Sc., Ph.D., University of Western Ontario;
Collip Medal;
Burroughs Wellcome Fund Hitchings-Elion Postdoctoral Fellow, University of Oxford;
CIHR Postdoctoral Fellow, University of Oxford

Tel: (613) 533-3188
Fax: (613) 533-2497
email: sps1@post.queensu.ca

  NMR spectroscopy is widely used to determine the 3D structures of globular proteins, multi-modular proteins, and protein-ligand complexes. Protein NMR has structural insight into multi-modular protein assembly and function as well as a variety of health disorders.

Our lab is currently interested in proteins of three biological systems or processes:

  1. the structural aspects behind the assembly of the cellulose-degrading complex in thermophile bacteria;

  2. apo(a) kringle assembly and interactions;

  3. calcium activation of the Ca2+-dependent thiol protease calpain.
Numerous bacteria and fungi require a multisubunit enzymatic complex called the 'cellulosome' to degrade crystalline cellulose. Cellulosomal assembly involves the integration of cellolosic enzymes into the complex and its attachment to the cell surface, with both processes being mediated by the non-covalent, calcium-dependent dockerin-cohesin protein interaction. Our research involves the use of NMR and other biophysical techniques to elucidate the mechanism of this calcium-dependent interaction including the solution structure determination of the individual dockerin and cohesin modules and the dockerin-cohesin complex.

Apo(a) is a unique component of Lp(a), which has been identified as a risk factor in atherosclerotic disorders. Apo(a) is modular protein consisting of multiple kringle modules which interact with numerous extracellular ligands. In collaboration with Dr. Marlys Koschinsky, we are carrying out NMR structural studies on individual kringle modules, multiple kringle module constructs and monitoring their interactions with various ligands using a variety of biophysical techniques. It is anticipated that these studies will provide significant biochemical and structural insight into the function and assembly of Lp(a) in health and disease.

Calpain is a multi-modular enzyme with calcium-dependent cysteine protease activity. In collaboration with Dr. Peter Davies, we are studying the calcium-binding events and realignment of domains I and II of the active site, which are required for enzymatic activation. We will also use NMR to monitor binding between various domains of calpain and peptide ligands to characterize domain-domain interactions.

  Pickford, A. R., Smith, S. P., Staunton, D., Boyd, J., and Campbell, I. D. (2001) The hairpin structure of the 6F11F22F2 fragment from human fibronectin enhances gelatin binding. EMBO J. 20, 1519-1529

Smith, S. P., Hashimoto, Y., Pickford, A. R., Campbell, I. D, and Werner, J. M. (2000) Interface characterisation of the type II module pair of fibronectin. Biochemistry 39, 8374-8381.

Smith, S. P. and Shaw, G. S. (1998) The change in hand mechanism for S100 signalling. Biochem. Cell Biol. 76, 324-333.

Smith, S. P. and Shaw, G. S. (1998) A novel calcium-sensitive switch revealed by the structure of human S100B in the calcium-bound form. Structure 6, 211-222