Ph.D. Biochemistry, University of Paris, 1986
Associate Professor
Center for Advanced Research in Biotechnology
9600 Gudelsky Dr.
Rockville, MD 20850 USA
Phone: (301)-738-6243
E-mail: mariuzza@carb.nist.gov
Research: Molecular Immunology.
Research in our laboratory is directed at understanding the molecular basis of antigen recognition by the immune system. Two classes of antigen recognition molecules are under study: antibodies and T-cell receptors (TcRs).
Structure-function studies of antigen-antibody reactions:
We are using the anti-lysozyme antibody D1.3 as a model for elucidating the principles governing macromolecular recognition by immunoglobulins. We have chosen to work with the protein-engineered, bacterially-expressed Fv fragment of D1.3 since the three-dimensional structures of the free Fv and that of the Fv-HEL complex are known to high resolution (1.8 Å ). Site-directed mutants designed to investigate particular aspects of the association reaction are being characterized by X-ray crystallography in order to precisely ascertain the effects of particular amino acid substitutions at the structural level. In parallel, we are using titration calorimetry to determine the affinity and entropy and enthalpy changes of the binding reactions with the aim of correlating these thermodynamic parameters with the X-ray models.
Antigen recognition
by TcRs:
Unlike antibodies which recognize antigen alone, TcRs recognize antigen
only in the form of peptides bound to molecules of the major histocompatibility
complex (MHC). Past efforts to undertake structural studies of TcRs, which are
composed of alpha and beta chains, have been hindered by difficulties
in producing large quantities of soluble forms of these transmembrane proteins
and in growing crystals suitable for high resolutions X-ray diffraction analysis.
We have so far obtained crystals of the extracellular portion of the beta chain
of a TcR specific for a hemagglutinin peptide of influenza virus in the context
of the MHC class II I-Ed molecule which diffract to beyond 2.0 Å
resolution. We have also crystallized a bacterially produced alpha chain
from a TcR specific for the N-terminal nonapeptide of myelin basic protein (a
self antigen) in association with I-Au; these crystals diffract to
beyond 2.2 Å resolution. Determination of the three-dimensional structures
of these recombinant molecules will enable us to define the basic molecular
architecture of both chains of alpha/beta TcRs; this should advance our
understanding of antigen recognition by this class of receptors.
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