1e12
From Proteopedia
HALORHODOPSIN, A LIGHT-DRIVEN CHLORIDE PUMP
Overview
Halorhodopsin, an archaeal rhodopsin ubiquitous in Haloarchaea, uses light energy to pump chloride through biological membranes. Halorhodopsin crystals were grown in a cubic lipidic phase, which allowed the x-ray structure determination of this anion pump at 1.8 angstrom resolution. Halorhodopsin assembles to trimers around a central patch consisting of palmitic acid. Next to the protonated Schiff base between Lys(242) and the isomerizable retinal chromophore, a single chloride ion occupies the transport site. Energetic calculations on chloride binding reveal a combination of ion-ion and ion-dipole interactions for stabilizing the anion 18 angstroms below the membrane surface. Ion dragging across the protonated Schiff base explains why chloride and proton translocation modes are mechanistically equivalent in archaeal rhodopsins.
About this Structure
1E12 is a Single protein structure of sequence from Halobacterium salinarum. The following page contains interesting information on the relation of 1E12 with [Bacteriorhodopsin]. Full crystallographic information is available from OCA.
Reference
Structure of the light-driven chloride pump halorhodopsin at 1.8 A resolution., Kolbe M, Besir H, Essen LO, Oesterhelt D, Science. 2000 May 26;288(5470):1390-6. PMID:10827943 Page seeded by OCA on Fri May 2 14:31:42 2008
