Rapid amyloid fibril formation by a winter flounder antifreeze protein requires specific interaction with ice

Abstract

A typically α-helical antifreeze protein (wflAFP-6) from winter flounder, Pseudopleuronectes americanus, forms amyloid fibrils during freezing. In this study, the effects of distinct components of the freezing process were examined. Freezing of wflAFP-6 in the presence of template ice was shown to be necessary for rapid conversion to an amyloid conformation. Neither subfreezing temperature nor phase change was sufficient. Thus, specific interaction with the ice surface was essential. The ice-induced formation of amyloid appeared to be unique to this helical antifreeze, it required high concentrations of protein and it occurred over a range of pH values. These results define a method for rapid formation of amyloid by wflAFP-6 on demand under physiological conditions.