Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.
OptoBioTechnology Research Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.
J Phys Chem Lett. 2020 Oct 15;11(20):8604-8609. doi: 10.1021/acs.jpclett.0c02383. Epub 2020 Sep 28.
Heliorhodopsin (HeR), a recently discovered new rhodopsin family, has an inverted membrane topology compared to animal and microbial rhodopsins, and no ion-transport activity. The slow photocycle of HeRs suggests a light-sensor function, although the function remains unknown. HeRs exhibit no specific binding of monovalent cations or anions. Despite this, ATR-FTIR spectroscopy in the present study demonstrates binding of Zn to HeR from (TaHeR). The biding of Zn to 0.2 mM is accompanied by helical structural perturbations without altering its color. Even though ion-specific FTIR spectra were observed for many divalent cations, only helical structural perturbations were observed for Zn-binding. Similar results were obtained for HeR 48C12. These findings suggest a possible modification of HeR function by Zn.
盐杆菌视紫红质（HeR）是最近发现的一种新型视紫红质家族，与动物和微生物视紫红质相比，它具有反转的膜拓扑结构，并且没有离子转运活性。HeR 的缓慢光循环表明它具有光感受器功能，但其功能仍然未知。HeR 不表现出对单价阳离子或阴离子的特异性结合。尽管如此，本研究中的 ATR-FTIR 光谱表明，锌与 （TaHeR） 中的 HeR 结合。当 Zn 结合到 0.2mM 时，会伴随着螺旋结构的扰动，而不会改变其颜色。尽管观察到许多二价阳离子的离子特异性 FTIR 光谱，但仅观察到 Zn 结合引起的螺旋结构扰动。对于 HeR 48C12 也得到了类似的结果。这些发现表明 Zn 可能会修饰 HeR 的功能。
