Asymmetric inclusion by de novo designed proteins: fluorescence probe studies on amphiphilic alpha-helix bundles.
The inclusion feature and supersecondary structure of the de novo designed proteins which are constructed with several amphiphilic alpha-helices and flexible linkage parts were investigated with fluorescence probes. Five types of small proteins (or peptides) have been designed, which are composed of 2, 3, 4, 4, and 6 helices, respectively, and are linked with only linear junctions except for one of 4-helix proteins. All of these proteins have inclusion ability for hydrophobic fluorophores. Further, by the analysis of fluorescence polarization anisotropy, it was suggested that these proteins include guest molecules in compact helix bundles constructed with about 4 helices. Asymmetric inclusion of both monomer and stacked dimer of acridine orange derivatives was found by means of induced circular dichroism except for the 4-helix protein with cross-junction. The chirality of the included dimer proved to be in accordance with the chiral sense of alpha-helical coiled-coil. The 6-helix protein has especially high efficiency in inclusion for any fluorophores examined in this study and brings about a significant blue-shift of maximal emission for 8-anilino-1-naphthalenesulfonate.
Morii
H
H
Research Institute for Polymers and Textiles, Ibaraki, Japan.
Ichimura
K
K
Uedaira
H
H
D000165:Acridine Orange / Q000737:chemistry; D000595:Amino Acid Sequence; D000817:Anilino Naphthalenesulfonates / Q000737:chemistry; D000818:Animals; D002942:Circular Dichroism; D004161:Diphenylhexatriene / Q000737:chemistry; D005456:Fluorescent Dyes; D008969:Molecular Sequence Data; D011487:Protein Conformation; D015202:Protein Engineering; D011506:Proteins / Q000138:chemical synthesis / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D011506:Proteins; D004161:Diphenylhexatriene; C027132:1-anilino-8-naphthalenesulfonate; D000165:Acridine Orange