| |
[1] Membrane suspended nanocompartments as a new artificial membrane system for studying light-activated proton pumps and channels
[2] Generation of flavoproteins with modified chromophores in vivo
[3] Role of the compound eyes and extraretinal photoreceptors in synchronizing the activity rhythm of Drosophila melanogaster to light-dark (LD) cycles.
[4] Biochemical studies on FAD derivates
[5] In vitro characterisation of "Channelopsins" from Chlamydomonas reinhardtii
[6] Photophysical and Photochemical Studies on Open-Chain Tetrapyrrole Complexes
[7] Investigation of the photocycle of a plant photoreceptor by Quantum Chemical Calculations and Molecular Dynamics Simulations
For detailed information about announced projects hit one of the links belowchoose number: [1] [2] [3] [4] [5] [6] [7]
project number [5] In vitro characterisation of "Channelopsins" from Chlamydomonas reinhardtii
Mammalian vision uses rhodopsin as the photoreceptor for light absorption and a G-proteins based enzymatic cascade, which leads to the closing of cation channels (Kaupp 1995; Okada et al., 2001; Sakmar et al., 2002). In invertebrates "light-sensitive" ion channels are switched by rhodopsin via a PLC-signaling cascade (Zuker, 1996; Hardie, 2001). In eubacteria and archeae sensory rhodopsins absorb the light and transduce the information chemically to the flagellar motor by using a two component system.
In the phototactic green alga Chlamydomonas, two microbial type rhodopsins were recently identified that comprise significant homology to sensory rhodopsins from Halobacterium salinarium (Hegemann et al., 2001; Nagel et al., 2002; Sineshchekov et al., 2002). In cooperation with Georg Nagel (MPI Frankfurt) we have demonstrated that both function as light-switched cation channels with more or less pronounced selectivity for H+ (Nagel et al., 2002). Both represent a new principle of how light absorption initiates extremely fast transmembrane cation fluxes and regulation of intracellular cation changes. We are looking for a graduate student, who is interested in the expression of these „Channelopsins“ and the biochemical and biophysical characterization. Since we would like to express both proteins in various eucaryotic systems (like SF9 cells, HEK293 and BHK cells), we are expecting a solid background in molecular biology and/or biochemistry but also interest in photobiology and biophysics.
Literature:
- Hegemann, P., Fuhrmann, M., Kateriya, S. Algal Sensory Photoreceptors. J. Phycol. 37, 668 (2001)
- Hardie RC, Raghu P. Visual transduction in Drosophila. Nature. 413, 186-93. (2001)
- Kaupp U. B. Family of cyclic nucleotide gated ion channels. Curr Opin Neurobiol. 5, 434 (1995)
- Nagel, G., D. Ollig, M. Fuhrmann, S. Kateriya, A.M. Musti, E. Bamberg, P. Hegemann. Channelrhodopsin-1: a light-gated proton channel in green algae. Science 296, 2395 (2002).
- Okada T, Ernst OP, Palczewski K, Hofmann KP. Activation of rhodopsin: new insights from structural and biochemical studies. Trends Biochem Sci. 26:318-24. (2001)
- Sakmar TP, Menon ST, Marin EP, Awad ES. Rhodopsin: insights from recent structural studies. Annu Rev Biophys Biomol Struct. 31:443-84. (2002)
- Sineshchekov, O. A., Jung, K.-H., &. Spudich, J. L Two rhodopsins mediate phototaxis to low and high-intensity light in Chlamydomonas reinhardtii. Proc. Natl. Acad. Sci USA 99, 8689-8694 (2002).
- Zuker CS. The biology of vision of Drosophila. Proc Natl Acad Sci U S A. 93:571-6. (1996)
how to apply ... (in general)
|
|
|
