Effects of macromolecular crowding on the intrinsically disordered proteins c-Fos and p27(Kip1).
A number of biologically active proteins exhibit intrinsic structural disorder in vitro under thermodynamically ideal conditions. In vivo, however, proteins exist in a crowded, thermodynamically nonideal environment. We tested the hypothesis that intrinsically disordered proteins adopt stable structure under crowded conditions in which excluded volume is predicted to stabilize compact, native conformations. In the presence of macromolecular crowding agents, neither the intrinsically disordered C-terminal activation domain of c-Fos nor the kinase-inhibition domain of p27(Kip1) undergoes any significant conformational change that is detected by changes in either circular dichroism or fluorescence spectra. We conclude that molecular crowding effects are not necessarily sufficient to induce ordered structure in intrinsically disordered proteins.
Flaugh
S L
SL
Department of Biochemistry and Molecular Biology and Department of Chemistry, Colorado State University, Fort Collins, Colorado, 80523-1870, USA.
Lumb
K J
KJ
D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D004926:Escherichia coli; D006801:Humans; D046911:Macromolecular Substances; D017510:Protein Folding; D017433:Protein Structure, Secondary; D016760:Proto-Oncogene Proteins c-fos / Q000737:chemistry* / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000737:chemistry* / Q000378:metabolism
D018797:Cell Cycle Proteins; D046911:Macromolecular Substances; D016760:Proto-Oncogene Proteins c-fos; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D018844:Cyclin-Dependent Kinases