1HQL

The xenograft antigen in complex with the B4 isolectin of Griffonia simplicifolia lectin-1

Summary for 1HQL

• Entry DOI: 10.2210/pdb1hql/pdb
• Related: 1GNZ 1GSL
• Descriptor: LECTIN, alpha-D-galactopyranose-(1-3)-methyl beta-D-galactopyranoside, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (6 entities in total)
• Functional Keywords: griffonia simplicifolia, lectin, xenograft antigen, sugar binding protein
• Biological source: Griffonia simplicifolia
• Total number of polymer chains: 2
• Total formula weight: 58377.89

Authors

Tempel, W.,Lipscomb, L.A.,Rose, J.P.,Woods, R.J. (deposition date: 2000-12-18, release date: 2002-01-16, Last modification date: 2024-10-30)

Primary citation

Tempel, W.,Tschampel, S.,Woods, R.J.
The xenograft antigen bound to Griffonia simplicifolia lectin 1-B(4). X-ray crystal structure of the complex and molecular dynamics characterization of the binding site.
J.Biol.Chem., 277:6615-6621, 2002

PubMed Abstract: The shortage of organs for transplantation into human patients continues to be a driving force behind research into the use of tissues from non-human donors, particularly pig. The primary barrier to such xenotransplantation is the reaction between natural antibodies present in humans and Old World monkeys and the Gal alpha(1-3)Gal epitope (xenograft antigen, xenoantigen) found on the cell surfaces of the donor organ. This hyperacute immune response leads ultimately to graft rejection. Because of its high specificity for the xenograft antigen, isolectin 1-B(4) from Griffonia simplicifolia (GS-1-B(4)) has been used as an immunodiagnostic reagent. Furthermore, haptens that inhibit natural antibodies also inhibit GS-1-B(4) from binding to the xenoantigen. Here we report the first x-ray crystal structure of the xenograft antigen bound to a protein (GS-1-B(4)). The three-dimensional structure was determined from orthorhombic crystals at a resolution of 2.3 A. To probe the influence of binding on ligand properties, we report also the results of molecular dynamics (MD) simulations on this complex as well as on the free ligand. The MD simulations were performed with the AMBER force-field for proteins augmented with the GLYCAM parameters for glycosides and glycoproteins. The simulations were performed for up to 10 ns in the presence of explicit solvent. Through comparison with MD simulations performed for the free ligand, it has been determined that GS-1-B(4) recognizes the lowest energy conformation of the disaccharide. In addition, the x-ray and modeling data provide clear explanations for the reported specificities of the GS-1-B(4) lectin. It is anticipated that a further understanding of the interactions involving the xenograft antigen will help in the development of therapeutic agents for application in the prevention of hyperacute xenograft rejection.

PubMed: 11714721
DOI: 10.1074/jbc.M109919200

Experimental method

X-RAY DIFFRACTION (2.2 Å)