Phage display and peptide mapping of an immunoglobulin light chain fibril-related conformational epitope

Biochemistry. 2007 Nov 13;46(45):13049-58. doi: 10.1021/bi701255m. Epub 2007 Oct 18.


Amyloid fibrils and partially unfolded intermediates can be distinguished serologically from native amyloidogenic precursor proteins or peptides. In this regard, we previously had reported that mAb 11-1F4, generated by immunizing mice with a thermally denatured variable domain (VL) fragment of the human kappa4 Bence Jones protein Len, bound to a non-native conformational epitope located within the N-terminal 18 residues of fibrillar, as well as partially denatured, Ig light chains (O'Nuallain, B., et al. (2006) Biochemistry 46, 1240-1247). To define further the antibody binding site, we used random peptide phage display and epitope mapping of VL Len using wild-type and alanine-mutated Len peptides where it was shown that the antibody epitope was reliant on up to 10 of the first 15 residues of protein Len. Comparison of Vkappa and Vlambda N-terminal germline consensus sequences with protein Len and 11-1F4-binding phages indicated that this antibody's cross-reactivity with light chains was related to an invariant proline at position(s) 7 and/or 8, bulky hydrophobic residues at positions 11 and 13, and additionally, to the ability to accommodate amino acid diversity at positions 1-4. Sequence alignments of the phage peptides revealed a central proline, often flanked by aromatic residues. Taken together, these results have provided evidence for the structural basis of the specificity of 11-1F4 for both kappa and lambda light chain fibrils. We posit that the associated binding site involves a rare type VI beta-turn or touch-turn that is anchored by a cis-proline residue. The identification of an 11-1F4-related mimotope should facilitate development of pan-light chain fibril-reactive antibodies that could be used in the diagnosis and treatment of patients with AL amyloidosis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amyloid / chemistry*
  • Amyloid / immunology*
  • Antibodies, Monoclonal / immunology
  • Bence Jones Protein / chemistry
  • Bence Jones Protein / immunology
  • Epitope Mapping
  • Epitopes*
  • Immunoglobulin Light Chains / chemistry*
  • Peptide Library
  • Protein Conformation
  • Sequence Alignment


  • Amyloid
  • Antibodies, Monoclonal
  • Epitopes
  • Immunoglobulin Light Chains
  • Peptide Library
  • Bence Jones Protein