Fischer Amanda J, Lagarias J Clark
Section of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA.
Proc Natl Acad Sci U S A. 2004 Dec 14;101(50):17334-9. doi: 10.1073/pnas.0407645101. Epub 2004 Nov 17.
Directed evolution of a cyanobacterial phytochrome was undertaken to elucidate the structural basis of its light sensory activity by remodeling the chemical environment of its linear tetrapyrrole prosthetic group. In addition to identifying a small region of the apoprotein critical for maintaining phytochrome's native spectroscopic properties, our studies revealed a tyrosine-to-histidine mutation that transformed phytochrome into an intensely red fluorescent biliprotein. This tyrosine is conserved in all members of the phytochrome superfamily, implicating direct participation in the primary photoprocess of phytochromes. Fluorescent phytochrome mutants also hold great promise to expand the present repertoire of genetically encoded fluorescent proteins into the near infrared.
通过重塑其线性四吡咯辅基的化学环境，对蓝细菌光敏色素进行定向进化，以阐明其光感受活性的结构基础。除了确定脱辅基蛋白的一个小区域对维持光敏色素的天然光谱特性至关重要外，我们的研究还发现了一个酪氨酸到组氨酸的突变，该突变将光敏色素转化为一种强烈红色荧光的双蛋白。这种酪氨酸在光敏色素超家族的所有成员中都是保守的，这意味着它直接参与了光敏色素的初级光过程。荧光光敏色素突变体也很有希望将目前遗传编码荧光蛋白的种类扩展到近红外区域。
