Quantitating denaturation by formic acid: imperfect repeats are essential to the stability of the functional amyloid protein FapC
Line Friis Bakmann Christensen, Jan Stanislaw Nowak, Thorbjørn Vincent Sønderby, Signe Andrea Frank, Daniel E. Otzen
Abstract
We then measured the solubilization of fibrils formed from different FapC variants with varying numbers of repeats as a function of the concentration of FA. This revealed a decline in the number of residues driving amyloid formation upon deleting at least two repeats. The midpoint of denaturation declined with the removal of repeats. Complete removal of all repeats led to fibrils that were solubilized at FA concentrations 2-3 orders of magnitude lower than the repeat-containing variants, showing that at least one repeat is required for the stability of functional amyloid.
Topics & Concepts
Formic acidAmyloid (mycology)Denaturation (fissile materials)ChemistryBiochemistryBiophysicsBiologyNuclear chemistryInorganic chemistryProtein Structure and DynamicsEnzyme Structure and FunctionMicrobial Metabolic Engineering and Bioproduction