Structural Alterations within Native Amyloidogenic Immunoglobulin Light Chains

Edward G. Randles, James R. Thompson, Douglas J. Martin, Marina Ramirez-Alvarado

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Amyloid diseases are characterized by the misfolding of a precursor protein that leads to amyloid fibril formation. Despite the fact that there are different precursors, some commonalities in the misfolding mechanism are thought to exist. In light chain amyloidosis (AL), the immunoglobulin light chain forms amyloid fibrils that deposit in the extracellular space of vital organs. AL proteins are thermodynamically destabilized compared to non-amyloidogenic proteins and some studies have linked this instability to increased fibril formation rates. Here we present the crystal structures of two highly homologous AL proteins, AL-12 and AL-103. This structural study shows that these proteins retain the canonical germ line dimer interface. We highlight important structural alterations in two loops flanking the dimer interface and correlate these results with the somatic mutations present in AL-12 and AL-103. We suggest that these alterations are informative structural features that are likely contributing to protein instability that leads to conformational changes involved in the initial events of amyloid formation.

Original languageEnglish (US)
Pages (from-to)199-210
Number of pages12
JournalJournal of Molecular Biology
Volume389
Issue number1
DOIs
StatePublished - May 29 2009

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Keywords

  • amyloid
  • immunoglobulin light chain
  • light chain amyloidosis
  • protein misfolding
  • X-ray crystallography

ASJC Scopus subject areas

  • Molecular Biology

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