Mechanical Unfoldons as Building Blocks of Maltose-binding Protein

Morten Bertz, Matthias Rief

Research output: Contribution to journalArticle

57 Citations (Scopus)


Identifying independently folding cores or substructures is important for understanding and assaying the structure, function and assembly of large proteins. Here, we suggest mechanical stability as a criterion to identify building blocks of the 366 amino acid maltose-binding protein (MBP). We find that MBP, when pulled at its termini, unfolds via three (meta-) stable unfolding intermediates. Consequently, the MBP structure consists of four structural blocks (unfoldons) that detach sequentially from the folded structure upon force application. We used cysteine cross-link mutations to characterize the four unfoldons structurally. We showed that many MBP constructs composed of those building blocks indeed form stably folded structures in solution. Mechanical unfoldons may provide a new tool for a systematic search for stable substructures of large proteins.

Original languageEnglish
Pages (from-to)447-458
Number of pages12
JournalJournal of Molecular Biology
Issue number2
Publication statusPublished - 2008 Apr 25
Externally publishedYes


  • atomic force microscopy
  • energy landscape
  • protein folding
  • single-molecule force spectroscopy
  • unfolding intermediate

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

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