Lee Sang-Soo, Choi Ah Reum, Kim So Young, Kang Ho-Won, Jung Kwang-Hwan, Lee Jung-Ha
Department of Life Science, Sogang University, Seoul 121-742, Republic of Korea.
J Nanosci Nanotechnol. 2011 May;11(5):4596-600. doi: 10.1166/jnn.2011.3650.
We cloned an intronless, nuclear-encoded opsin gene from an EST library of Acetabularia acetabulum. Acetabularia rhodopsin I (ARI) encodes a protein of 246 amino acids with molecular weight of 27 kDa. ARI was reconstituted in the Xenopus oocyte expression system to characterize its electrophysiological properties utilizing the two-electrode voltage-clamping technique. Oocytes where ARI cRNA was injected displayed outward directed currents in response to light. The maximum action spectrum of ARI was detected at 520 nm green light. Light-stimulated ARI current amplitude was altered by the protons, but not by the other ions in recording solutions, suggesting that the algal rhodopsin is a light-stimulated proton pump. Typical proton-mediated outward current elicited by 520 nm light was characterized with two phases of non-inactivating outward current following initial transient current. Taken together, we here reported cloning of a novel Acetabularia opsin gene which was characterized to be a proton-pump stimulated by light.
我们从伞藻的一个EST文库中克隆了一个无内含子、核编码的视蛋白基因。伞藻视紫红质I（ARI）编码一种由246个氨基酸组成、分子量为27 kDa的蛋白质。利用双电极电压钳技术，在非洲爪蟾卵母细胞表达系统中重组ARI，以表征其电生理特性。注射了ARI cRNA的卵母细胞在光照下显示出外向电流。ARI的最大作用光谱在520 nm绿光处检测到。光照刺激的ARI电流幅度受质子影响，但不受记录溶液中其他离子影响，这表明藻类视紫红质是一种光刺激质子泵。由520 nm光引发的典型质子介导外向电流的特征是，在初始瞬态电流之后有两个非失活外向电流阶段。综上所述，我们在此报道了一个新的伞藻视蛋白基因的克隆，其特征是一种受光刺激的质子泵。
