Michael GroB Pages 339 - 347 ( 9 )
The sequence of a protein normally determines which amino acid residues will form a helices, and which one b sheets, to an extent that allows secondary structure prediction to be made with a reasonable reliability. Nevertheless, non-native helical structures are observed during in vitro folding of several model proteins and may even occur during protein biosynthesis within the ribosomal exit tunnel. Moreover, non-native b sheet structures are common in amyloid fibrils formed by a variety of pathogenic and even non-pathogenic proteins and peptides. In all of these cases, the formation of a helix precedes the appearance of b sheet, which suggests that conversion from the simpler, more local helix structure to the often more convoluted sheet architecture during folding and pathogenic misfolding processes could be a unifying principle of general importance. A better understanding of this switching process, and the ability to design molecular systems which can be induced to switch between these conformations will have a significant impact on fields ranging from fundamental biochemistry through to applied technology and medicine.
Helix, helical native, amyloid, transthyretin
Oxford Centre for MolecularSciences, University of Oxford, New Chemistry Laboratory, Oxford OX13QT, UK