Hsu D S, Zhao X, Zhao S, Kazantsev A, Wang R P, Todo T, Wei Y F, Sancar A
Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill 27599, USA.
Biochemistry. 1996 Nov 5;35(44):13871-7. doi: 10.1021/bi962209o.
Recently, a human cDNA clone with high sequence homology to the photolyase/blue-light photoreceptor family was identified. The putative protein encoded by this gene exhibited a strikingly high (48% identity) degree of homology to the Drosophila melanogaster (6-4) photolyase [Todo et al. (1996) Science 272, 109-112]. We have now identified a second human gene whose amino acid sequence displays 73% identity to the first one and have named the two genes CRY1 and CRY2, respectively. The corresponding proteins hCRY1 and hCRY2 were purified and characterized as maltose-binding fusion proteins. Similar to other members of the photolyase/blue-light photoreceptor family, both proteins were found to contain FAD and a pterin cofactor. Like the plant blue-light photoreceptors, both hCRY1 and hCRY2 lacked photolyase activity on the cyclobutane pyrimidine dimer and the (6-4) photoproduct. We conclude that these newly discovered members of the photolyase/photoreceptor family are not photolyases and instead may function as blue-light photoreceptors in humans.
最近，人们鉴定出了一个与光解酶/蓝光光感受器家族具有高度序列同源性的人类cDNA克隆。该基因编码的推定蛋白与黑腹果蝇（6-4）光解酶表现出极高的同源性（48%的一致性）[户堂等人（1996年），《科学》272卷，第109 - 112页]。我们现在又鉴定出了另一个人类基因，其氨基酸序列与第一个基因有73%的一致性，我们分别将这两个基因命名为CRY1和CRY2。相应的蛋白质hCRY1和hCRY2被纯化，并被鉴定为麦芽糖结合融合蛋白。与光解酶/蓝光光感受器家族的其他成员相似，这两种蛋白质都被发现含有黄素腺嘌呤二核苷酸（FAD）和一个蝶呤辅因子。与植物蓝光光感受器一样，hCRY1和hCRY2对环丁烷嘧啶二聚体和（6-4）光产物都缺乏光解酶活性。我们得出结论，光解酶/光感受器家族的这些新发现成员不是光解酶，而是可能在人类中作为蓝光光感受器发挥作用。
