Analysis of the molecular properties of vertebrate novel UV-absorbing proteins

我们分析了Opn 5组的分子特性，Opn 5组包含广泛分布于脊椎动物中的光感受蛋白。我们发现，在Opn 5组的几个亚组中，Opn 5 m和Opn 5L 2可以结合11-cis-retinal形成UV敏感色素，并且光异构化为全反式retinal导致G蛋白活化。此外，非哺乳动物的Opn 5 m和Opn 5L 2也可以直接结合全反式视黄醇，从而在没有光照射的情况下激活G蛋白。这些数据表明，Opn 5蛋白可能为脊椎动物（包括人类）的UV接收提供分子基础，并且非哺乳动物Opn 5蛋白也负责非光感受功能。

We analyzed the molecular properties of Opn5 group which contains photoreceptive proteins widely distributed in vertebrates. We revealed that, among several subgroups of Opn5 group, Opn5m and Opn5L2 can bind 11-cis-retinal to form UV-sensitive pigments and photoisomerization into all-trans-retinal results in G protein activation. In addition, non-mammalian Opn5m and Opn5L2 can also directly bind all-trans-retinal to activate G protein without light irradiation. These data suggest that Opn5 proteins possibly provide the molecular basis for UV reception in vertebrates including humans and non-mammalian Opn5 proteins are also responsible for non-photoreceptive function.