Localization of a Conformational Epitope Common to Non-Native and Fibrillar Immunoglobulin Light Chains
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- 作者：Brian O'Nuallain ; Amy Allen ; Stephen J. Kennel ; Deborah T. Weiss ; Alan Solomon ; Jonathan S. Wall
- 刊名：Biochemistry
- 出版年：2007
- 出版时间：February 6, 2007
- 年：2007
- 卷：46
- 期：5
- 页码：1240 - 1247
- 全文大小：472K
- 年卷期：v.46,no.5(February 6, 2007)
- ISSN：1520-4995
文摘
Amyloid fibrils and partially unfolded intermediates may be distinguished serologically fromnative amyloidogenic precursor proteins or peptides. In this regard, we had previously reported that theIgG1 mAb 11-1F4, generated by immunizing mice with a thermally denatured variable region fragmentof the human Ig
4 Bence Jones protein Len, reacted specifically with light chain (LC) fibrils, irrespectiveof or 
isotype but, notably, did not with native molecules (Hrncic, R. et al. (2000) Am. J. Pathol. 157,1239-1246). To elucidate the molecular basis of this specificity, we have used a europium-linkedfluorescent immunoassay, where it was demonstrated through epitope mapping that mAb 11-1F4 recognizesa conformational determinant contained within the first (N-terminal) 18 amino acids of misfolded LCs.The nature of this epitope was evidenced in competition studies where the peptide Len (1-18), but notthe intact protein or other LCs, inhibited the binding of the antibody to fibrils. This unique reactivity wasdependent on the structural integrity of this portion of the molecule, particularly the presence of a highlyconserved prolyl residue at position 8. On the basis of our experimental data, we posit that the mAb11-1F4 binding site found on partially denatured and fibrillar LCs involves an inducible N-terminal mainchain reversal that results in the formation of a proline anchored 
-turn. Our delineation of this LC fibril-associated epitope provides the rationale for the design of novel amyloid-reactive antibodies with diagnosticand therapeutic potential for patients with LC-associated and other forms of amyloidosis.
4 Bence Jones protein Len, reacted specifically with light chain (LC) fibrils, irrespectiveof or isotype but, notably, did not with native molecules (Hrncic, R. et al. (2000) Am. J. Pathol. 157,1239-1246). To elucidate the molecular basis of this specificity, we have used a europium-linkedfluorescent immunoassay, where it was demonstrated through epitope mapping that mAb 11-1F4 recognizesa conformational determinant contained within the first (N-terminal) 18 amino acids of misfolded LCs.The nature of this epitope was evidenced in competition studies where the peptide Len (1-18), but notthe intact protein or other LCs, inhibited the binding of the antibody to fibrils. This unique reactivity wasdependent on the structural integrity of this portion of the molecule, particularly the presence of a highlyconserved prolyl residue at position 8. On the basis of our experimental data, we posit that the mAb11-1F4 binding site found on partially denatured and fibrillar LCs involves an inducible N-terminal mainchain reversal that results in the formation of a proline anchored -turn. Our delineation of this LC fibril-associated epitope provides the rationale for the design of novel amyloid-reactive antibodies with diagnosticand therapeutic potential for patients with LC-associated and other forms of amyloidosis.