3d6g
Fc fragment of IgG1 (Herceptin) with protein-A mimetic peptide dendrimer ligand.
Structural highlights
DiseaseIGHG1_HUMAN Defects in IGHG1 are a cause of multiple myeloma (MM) [MIM:254500. MM is a malignant tumor of plasma cells usually arising in the bone marrow and characterized by diffuse involvement of the skeletal system, hyperglobulinemia, Bence-Jones proteinuria and anemia. Complications of multiple myeloma are bone pain, hypercalcemia, renal failure and spinal cord compression. The aberrant antibodies that are produced lead to impaired humoral immunity and patients have a high prevalence of infection. Amyloidosis may develop in some patients. Multiple myeloma is part of a spectrum of diseases ranging from monoclonal gammopathy of unknown significance (MGUS) to plasma cell leukemia. Note=A chromosomal aberration involving IGHG1 is found in multiple myeloma. Translocation t(11;14)(q13;q32) with the IgH locus. Translocation t(11;14)(q13;q32) with CCND1; translocation t(4;14)(p16.3;q32.3) with FGFR3; translocation t(6;14)(p25;q32) with IRF4. FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedUnderstanding the chemical physical properties of protein binding sites is at the basis of the rational design of protein ligands. The hinge region of the Fc fragment of immunoglobulin G is an important and well characterized protein binding site, known to interact with several natural proteins and synthetic ligands. Here, we report structural evidence that a Staphylococcus aureus Protein A mimetic peptide dendrimer, deduced by a combinatorial approach, binds close to the Cgamma2/Cgamma3 interface of the constant fragment of a human IgG1 molecule, partially hindering the Protein A binding site. The X-ray analysis evidenced a primary binding site located between a terminal Arg residue of the ligand peptidic arm and a hydrophobic protein site consisting of Val308, Leu309, and His310. A molecular dynamic analysis of the model derived from the X-ray structure showed that in water at room temperature the complex is further stabilized by the formation of at least one more contact between a terminal Arg residue of the second arm of the peptide and the carboxylic group of a protein amino acid, such as Glu318, Asp312, or Asp280. It appears thus that stability of the Fc-dendrimer complex is determined by the synergetic formation of multiple bonds of different nature between the dendrimer arms and the protein accessible sites. The electrostatic and van der Waals energies of the complex were monitored during the MD simulations and confirmed the energetic stability of the two interactions. Structural characterization of a Protein A mimetic peptide dendrimer bound to human IgG.,Moiani D, Salvalaglio M, Cavallotti C, Bujacz A, Redzynia I, Bujacz G, Dinon F, Pengo P, Fassina G J Phys Chem B. 2009 Dec 17;113(50):16268-75. doi: 10.1021/jp909405b. PMID:19924842[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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