Fibrillation of the major curli subunit CsgA under a wide range of conditions implies a robust design of aggregation

Biochemistry. 2011 Oct 4;50(39):8281-90. doi: 10.1021/bi200967c. Epub 2011 Sep 12.

Abstract

The amyloid fold is usually considered a result of protein misfolding. However, a number of studies have recently shown that the amyloid structure is also used in nature for functional purposes. CsgA is the major subunit of Escherichia coli curli, one of the most well-characterized functional amyloids. Here we show, using a highly efficient approach to prepare monomeric CsgA, that in vitro fibrillation of CsgA occurs under a wide variety of environmental conditions and that the resulting fibrils exhibit similar structural features. This highlights how fibrillation is "hardwired" into amyloid that has evolved for structural purposes in a fluctuating extracellular environment and represents a clear contrast to disease-related amyloid formation. Furthermore, we show that CsgA polymerization in vitro is preceded by the formation of thin needlelike protofibrils followed by aggregation of the amyloid fibrils.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adhesins, Bacterial / chemistry*
  • Amyloid / chemistry*
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / metabolism
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / chemistry*
  • Hydrogen-Ion Concentration
  • Osmolar Concentration
  • Protein Structure, Quaternary

Substances

  • Adhesins, Bacterial
  • Amyloid
  • Bacterial Proteins
  • Escherichia coli Proteins
  • csgA protein, E coli
  • Crl protein, Bacteria