Dr. John L. Spudich

Membrane Protein Structure and Function

The primary interest in our laboratory is the mechanism by which photosensory receptors sense and transmit information concerning the color, intensity, and pattern of light in the environment. We study a widespread class of photoactive receptor proteins (rhodopsins) that consist of seven transmembrane helices connected by interhelical loops. The helices form a pocket for the photosensitive molecule vitamin-A aldehyde (retinal), and the receptor proteins physically couple to protein transducers that relay signals to sensory pathways in the cytoplasm. These photosensitive heptahelical proteins are used for visual processes of various degrees of sophistication, ranging from detection of light-dark boundaries, light gradients, and light direction by single-cell microorganisms to high-resolution color image detection by higher animal eyes

Selected References

Retinal and nearby residues in the photoactive site of sensory rhodopsin II.

Vogeley, L., Sineshchekov, O.A., Trivedi, V.D., Sasaki, J., Spudich, J.L. and Luecke, H. (2004) Anabaena Sensory Rhodopsin: A Photochromic Color Sensor at 2.0 Å. Science. Sep 30 [306, 1390-1393].

Yang, C.-S. Sineshchekov, O.A. Spudich, E.N. and Spudich, J.L. (2004) The cytoplasmic membrane-proximal domain of the HtrII transducer interacts with the E-F Loop of photoactivated Natronomonas pharaonis sensory rhodopsin II. J. Biol. Chem. Jul 15. 279:42970-42976.

Chen, X. and Spudich, J.L. (2004) Five residues in the HtrI transducer membrane-proximal domain close the cytoplasmic proton-conducting channel of sensory rhodopsin I. J. Biol. Chem., Jul 13. 279:42964-42969.

Govorunova, E.G., Jung, K.-H. Sineshchekov, O.A., and Spudich, J.L. (2004) Chlamydomonas sensory rhodopsins A and B: Cellular content and role in photophobic responses. Biophys. J. 86, 2342-2349.

Wang, W., Sineshchekov, O.A., Spudich, E.N., and Spudich, J.L. (2003) Spectroscopic and photochemical characterization of a deep ocean proteorhodopsin. J. Biol. Chem. 278, 33985-33991.

Man*, D., Wang*, W., Sabehi, G., Aravind, L., Post, A.F., Massana, R., Spudich, E.N., Spudich, J.L., and Béjà, O. (2003) Diversification and spectral tuning in marine proteorhodopsins. EMBO J., 8, 1725-1731. {*1st two authors equal contributors}.

Spudich, J.L. (2002) News & Views: Spotlight on Receptor-Transducer Interaction. Nature Struct. Biol. 9, 797-799.

Sineshchekov, O.A., Jung, K.-H. and Spudich, J.L. (2002) Two rhodopsins mediate phototaxis to low and high intensity light in Chlamydomonas reinhardtii. Proc. Natl. Acad. Sci. USA 99, 8689-8694.

Béjà*, O., Spudich*, E.N., Spudich, J.L., Leclerc, M. and DeLong, E.F. (2001) Proteorhodopsin phototrophy in the ocean. Nature, 411, 786-789 {*1st two authors equal contributors}.

Luecke, H., Schobert, B., Lanyi, J.K., Spudich, E.N., and Spudich, J.L. (2001) Crystal Structure of Sensory Rhodopsin II at 2.4 Å: Insights into Color Tuning and Transducer Interaction. Science 293, 1499-1503.

Surface of sensory rhodopsin II that interacts with its tranducer protein.