Identification of a new intermediate state that binds but not activates transducin in the bleaching process of bovine rhodopsin

FEBS Letters

Tachibanaki, Shuji¹  Terakita, Akihisa¹  Imai, Hiroo¹  Shichida, Yoshinori¹ 

[1] Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-01, Japan

关键词: Rhodopsin;    Transducin;    Photobleaching process;    Activation process;    GTPγS;    guanosine 5′-O-(3-thiotriphosphate);    ROS;    rod outer segment(s);    CHAPS;    3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate;    ConA;    concanavalin A;    HEPES;    N-(2-hydroxyethyl)piperazine-N′-2-ethanesulfonic acid;    PMSF;    phenylmethanesulfonyl fluoride;    DTT;    dithiothreitol;    PC;    l-α-phosphatidylcholine form egg yolk;   

DOI  :  10.1016/S0014-5793(98)00216-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Using time-resolved low-temperature spectroscopy, we have examined whether or not bovine rhodopsin has a unique transducin-binding state, meta I_b, previously detected from chicken rhodopsin. Unlike chicken meta I_b, bovine meta I_b was detected only by detailed kinetics analysis of the bleaching process, but it was stabilized by transducin and visualized in the observed spectral changes. From the effect of GTPγS, it was revealed that meta I_b induced no GDP-GTP exchange reaction in transducin. Thus meta I_b is a common intermediate of vertebrate rhodopsin and transducin is activated in two steps by meta I_b and meta II.

【 授权许可】

Unknown