User:Electriceel25/Halorhodopsin

Potential references for adding information:

 * 1) Essen, L.-O. (2002). Halorhodopsin: light-driven ion pumping made simple? Current Opinion in Structural Biology, 12(4), 516-522. https://doi.org/https://doi.org/10.1016/S0959-440X(02)00356-1
 * Ji, Z.-G., Ishizuka, T., & Yawo, H. (2013). Channelrhodopsins—Their potential in gene therapy for neurological disorders. Neuroscience Research, 75(1), 6-12. https://doi.org/10.1016/j.neures.2012.09.004
 * 1) Parrish, R. R., MacKenzie-Gray Scott, C., Jackson-Taylor, T., Grundmann, A., McLeod, F., Codadu, N. K., Călin, A., Alfonsa, H., Wykes, R. C., Voipio, J., & Trevelyan, A. J. (2023). Indirect Effects of Halorhodopsin Activation: Potassium Redistribution, Nonspecific Inhibition, and Spreading Depolarization. The Journal of Neuroscience, 43(5), 685. https://doi.org/10.1523/JNEUROSCI.1141-22.2022
 * 2) Zhang, C., Yang, S., Flossmann, T., Gao, S., Witte, O. W., Nagel, G., Holthoff, K., & Kirmse, K. (2019). Optimized photo-stimulation of halorhodopsin for long-term neuronal inhibition. BMC Biology, 17(1), 95. https://doi.org/10.1186/s12915-019-0717-6
 * 3) Lanyi, J. K. (1986). Halorhodopsin: A Light-Driven Chloride Ion Pump. Annual Review of Biophysics and Biophysical Chemistry, 15(1), 11-28. https://doi.org/10.1146/annurev.bb.15.060186.000303

Edits to make to Halorhodopsin Wikipedia page

 * Add categories/sections and organize current information into new sections
 * Etymology
 * Structure
 * History
 * Expand "As a research tool" section (possibly rename the section "Applications"?)
 * Include current use of halorhodopsins in optogenetics
 * Add missing link for "light-gated ion pump"
 * Add image of halorhodopsin structure from Wikimedia commons
 * Add 'See Also' section for links to other rhodopsin Wikipedia pages and Optogenetics Wikipedia page
 * Add a taxbox (similar to one on Proteorhodopsin Wikpedia page)

Article Draft
Halorhodopsin is a seven-transmembrane retinylidene protein from microbial rhodopsin family. It is a chloride-specific light-gated ion pump found in archaea known as halobacteria. It is activated by green light wavelengths of approximately 578nm. Halorhodopsin also shares sequence similarity to channelrhodopsin, another light-driven ion channel.

''Should this go in the introduction? Maybe move to a different section:''

Halorhodopsin contains the essential light-isomerizable vitamin A derivative all-trans-retinal. Due to the intense attention on solving the structure and function of this molecule, halorhodopsin is one of the few membrane proteins whose crystal structure is known.

History
Halorhodopsin was discovered in 1980 in Halobacterium salinarum, a salt-loving (halophilic) type of archaeon.

Structure
Halorhodopsin folds into a seven-transmembrane helix topology and has a similar tertiary structure (but not primary sequence structure) to vertebrate rhodopsins, the pigments that sense light in the retina.

Etymology
The name Halorhodopsin is of Greek origin, the halo- prefix emerging from ἅλς (háls) meaning "salt" or "sea". The suffix -rhodopsin originates from ῥόδον (rhódon, “rose”), due to its pinkish color, and ὄψις (ópsis, “sight”).

Applications
Halorhodopsin has been used in optogenetics to hyperpolarize (inhibit) specific neurons. Optogenetics has been proposed as therapeutic approach to neurological conditions for which current treatment methods are not always effective, including epilepsy and Parkinson's disease. NpHR has been used to inhibit excitatory neurons in the subthalamic nucleus of hemiparkinsonian rats, lesioned using the neurotoxin 6-OHDA.