Imperfect repeats in the functional amyloid protein FapC reduce the tendency to fragment during fibrillation

Casper B. Rasmussen, Gunna Christiansen, Brian S. Vad, Carina Lynggaard, Jan J. Enghild, Maria Andreasen*, Daniel Otzen

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

2 Citations (Scopus)


Functional amyloid (FA) is widespread in bacteria and serves multiple purposes such as strengthening of biofilm and contact with eukaryotic hosts. Unlike pathological amyloid, FA has been subjected to evolutionary optimization which is likely to be reflected in the aggregation mechanism. FA from different bacteria, including Escherichia coli (CsgA) and Pseudomonas (FapC), contains a number of imperfect repeats which may be key to efficient aggregation. Here we report on the aggregative behavior of FapC constructs which represent all single, double, and triple deletions of the protein's three imperfect repeats. Analysis of the fibrillation kinetics by the program Amylofit reveals that the removal of these repeats increases the tendency of the growing fibrils to fragment and also generally increases aggregation half-times. Remarkably, even the mutant lacking all three repeats was able to fibrillate, although fibrillation was much more irregular and led to significantly altered and destabilized fibrils. We conclude that imperfect repeats can promote fibrillation efficiency thanks to their modular design, though the context of the imperfect repeats also plays a significant role.

Original languageEnglish
JournalProtein Science
Pages (from-to)633-642
Number of pages10
Publication statusPublished - 1 Mar 2019


  • aggregation mechanisms
  • Amylofit
  • FapC
  • kinetic analysis
  • Thioflavin T


Dive into the research topics of 'Imperfect repeats in the functional amyloid protein FapC reduce the tendency to fragment during fibrillation'. Together they form a unique fingerprint.

Cite this