| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Biophysical Journal 60: 1490-1498 (1991)
© 1991 the Biophysical Society
Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461.
ABSTRACT
The strain CC-2359 of the unicellular eukaryotic alga Chlamydomonas reinhardtii originally described as a low pigmentation mutant is found to be devoid of photophobic stop responses to photostimuli over a wide range of light intensities. Photophobic responses of the mutant are restored by exogenous addition of all-trans retinal. We have combined computer-based cell-tracking and motion analysis with retinal isomer and retinal analog reconstitution of CC-2359 to investigate properties of the photophobic response receptor. Most rapid and most complete reconstitution is obtained with all-trans retinal compared to 13-cis, 11-cis, and 9-cis retinal. An analog locked by a carbon bridge in a 6-s-trans conformation reconstitutes whereas the corresponding 6-s-cis locked analog does not. Retinal analogs prevented from isomerization around the 13-14 double bond by a five-membered ring in the polyene chain (locked in either the 13-trans or 13-cis configuration) do not restore the response, but enter the chromophore binding pocket as evidenced by their inhibition of all-trans retinal regeneration of the response. Results of competition experiments between all-trans and each of the 13-locked analogs fit a model in which each chromophore exhibits reversible binding to the photoreceptor apoprotein. A competitive inhibition scheme closely fits the data and permits calculation of apparent dissociation constants for the in vivo reconstitution process of 2.5 x 10(-11) M, 5.2 x 10(-10) M, and 5.4 x 10(-9) M, for all-trans, 13-trans-locked and 13-cis-locked analogs, respectively. The chromophore requirement for the trans configuration and 6-s-trans conformation, and the lack of signaling function from analogs locked at the 13 position, are characteristic of archaebacterial rhodopsins, rather than the previously studied eukaryotic rhodopsins (i.e., visual pigments).
This article has been cited by other articles:
 |
|
 |
|
  O. P. Ernst, P. A. S. Murcia, P. Daldrop, S. P. Tsunoda, S. Kateriya, and P. Hegemann Photoactivation of Channelrhodopsin J. Biol. Chem., January 18, 2008; 283(3): 1637 - 1643. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. G. Govorunova, K.-H. Jung, O. A. Sineshchekov, and J. L. Spudich Chlamydomonas Sensory Rhodopsins A and B: Cellular Content and Role in Photophobic Responses Biophys. J., April 1, 2004; 86(4): 2342 - 2349. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Nagel, T. Szellas, W. Huhn, S. Kateriya, N. Adeishvili, P. Berthold, D. Ollig, P. Hegemann, and E. Bamberg Channelrhodopsin-2, a directly light-gated cation-selective membrane channel PNAS, November 25, 2003; 100(24): 13940 - 13945. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
O. A. Sineshchekov, K.-H. Jung, and J. L. Spudich Two rhodopsins mediate phototaxis to low- and high-intensity light in Chlamydomonasreinhardtii PNAS, June 7, 2002; (2002) 122243399. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Yoshimura and R. Kamiya The Sensitivity of Chlamydomonas Photoreceptor is Optimized for the Frequency of Cell Body Rotation Plant Cell Physiol., June 1, 2001; 42(6): 665 - 672. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Fuhrmann, A. Stahlberg, E. Govorunova, S. Rank, and P. Hegemann The abundant retinal protein of the Chlamydomonas eye is not the photoreceptor for phototaxis and photophobic responses J. Cell Sci., January 11, 2001; 114(21): 3857 - 3863. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
