Worthington Erin N, Kavakli I Halil, Berrocal-Tito Gloria, Bondo Bruce E, Sancar Aziz
Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA.
J Biol Chem. 2003 Oct 3;278(40):39143-54. doi: 10.1074/jbc.M305792200. Epub 2003 Jul 22.
The sequence of Vibrio cholerae genome revealed three genes belonging to the photolyase/cryptochrome blue-light photoreceptor family. The proteins encoded by the three genes were purified and characterized. All three proteins contain folate and flavin cofactors and have absorption peaks in the range of 350-500 nm. Only one of the three, VcPhr, is a photolyase specific for cyclobutane pyrimidine dimers. The other two are cryptochromes and were designated VcCry1 and VcCry2, respectively. Mutation of phr abolishes photoreactivation of UV-induced killing, whereas mutations in cry1 and cry2 do not affect photorepair activity. VcCry1 exhibits some unique features. Of all cryptochromes characterized to date, it is the only one that contains stoichiometric amounts of both chromophores and retains its flavin cofactor in the two-electron reduced FADH2 form. In addition, VcCry1 exhibits RNA binding activity and co-purifies with an RNA of 60-70 nucleotides in length.
霍乱弧菌基因组序列显示有三个基因属于光解酶/隐花色素蓝光光感受器家族。对这三个基因编码的蛋白质进行了纯化和特性分析。这三种蛋白质均含有叶酸和黄素辅因子，且吸收峰在350 - 500纳米范围内。这三种蛋白质中只有一种，即VcPhr，是一种特异性作用于环丁烷嘧啶二聚体的光解酶。另外两种是隐花色素，分别命名为VcCry1和VcCry2。phr突变会消除紫外线诱导杀伤的光复活作用，而cry1和cry2的突变则不影响光修复活性。VcCry1表现出一些独特的特征。在迄今为止已鉴定的所有隐花色素中，它是唯一一种含有化学计量的两种发色团且以双电子还原的FADH2形式保留其黄素辅因子的隐花色素。此外，VcCry1表现出RNA结合活性，并与长度为60 - 70个核苷酸的RNA共纯化。
