Beharry Andrew A, Sadovski Oleg, Woolley G Andrew
Department of Chemistry, University of Toronto, 80 St. George St.. Toronto, ON M5S 3H6, Canada.
Org Biomol Chem. 2008 Dec 7;6(23):4323-32. doi: 10.1039/b810533b. Epub 2008 Sep 24.
Azobenzene derivatives can be used to reversibly photo-regulate conformation and activity when introduced as intramolecular bridges in peptides and proteins. Here we report the design, synthesis, and characterization of an azobenzene derivative that absorbs between 400-450 nm in aqueous solution to produce the cis isomer, and relaxes back to the trans isomer with a half-life of a few seconds at room temperature. In the trans form, the linker can span a distance of approximately 25 A, so that it can bridge Cys residues spaced i, i + 15 in an alpha-helix. Switching of the azobenzene cross-linker from trans to cis causes a decrease in the helix content of peptides where the linker is attached via Cys residues spaced at i, i + 15 and i, i + 14 positions, no change in helix content with Cys residues spaced i, i + 11 and an increase in helix content in a peptide with Cys residues spaced at i, i + 7. In the presence of 10 mM reduced glutathione, the azobenzene cross-linker continued to photo-switch after 24 hours. This cross-linker design thus expands the possibilities for fast photo-control of peptide and protein structure in biochemical systems.
当偶氮苯衍生物作为分子内桥引入肽和蛋白质中时，可用于可逆地光调节其构象和活性。在此，我们报告了一种偶氮苯衍生物的设计、合成及表征，该衍生物在水溶液中于400 - 450 nm波长吸收光以产生顺式异构体，并在室温下以几秒的半衰期弛豫回到反式异构体。在反式构象中，连接基团可跨越约25埃的距离，从而能够连接α - 螺旋中i、i + 15位的半胱氨酸残基。偶氮苯交联剂从反式转变为顺式会导致连接基团通过i、i + 15位和i、i + 14位半胱氨酸残基连接的肽段螺旋含量降低，通过i、i + 11位半胱氨酸残基连接的肽段螺旋含量无变化，而通过i、i + 7位半胱氨酸残基连接的肽段螺旋含量增加。在10 mM还原型谷胱甘肽存在的情况下，偶氮苯交联剂在24小时后仍能继续进行光开关转换。因此，这种交联剂设计扩展了在生化系统中对肽和蛋白质结构进行快速光控的可能性。
