View source for 1r2n

[[Image:1r2n.gif|left|200px]]

 {{Structure
|PDB= 1r2n |SIZE=350|CAPTION= <scene name='initialview01'>1r2n</scene>
|SITE= 
|LIGAND= <scene name='pdbligand=RET:RETINAL'>RET</scene>
|ACTIVITY= 
|GENE= 
|DOMAIN=
|RELATEDENTRY=[[1brr|1BRR]], [[1c3w|1c3w]], [[1qhj|1qhj]]
|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1r2n FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1r2n OCA], [http://www.ebi.ac.uk/pdbsum/1r2n PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1r2n RCSB]</span>
}}

'''NMR structure of the all-trans retinal in dark-adapted Bacteriorhodopsin'''


==Overview==
The two forms of bacteriorhodopsin present in the dark-adapted state, containing either all-trans or 13-cis,15-syn retinal, were examined by using solution state NMR, and their structures were determined. Comparison of the all-trans and the 13-cis,15-syn forms shows a shift in position of about 0.25 A within the pocket of the protein. Comparing this to the 13-cis,15-anti chromophore of the catalytic cycle M-intermediate structure, the 13-cis,15-syn form demonstrates a less pronounced up-tilt of the retinal C12[bond]C14 region, while leaving W182 and T178 essentially unchanged. The N[bond]H dipole of the Schiff base orients toward the extracellular side in both forms, however, it reorients toward the intracellular side in the 13-cis,15-anti configuration to form the catalytic M-intermediate. Thus, the change of the N[bond]H dipole is considered primarily responsible for energy storage, conformation changes of the protein, and the deprotonation of the Schiff base. The structural similarity of the all-trans and 13-cis,15-syn forms is taken as strong evidence for the ion dipole dragging model by which proton (hydroxide ion) translocation follows the change of the dipole.

==About this Structure==
1R2N is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Halobacterium_salinarum Halobacterium salinarum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1R2N OCA]. 

==Reference==
The structures of the active center in dark-adapted bacteriorhodopsin by solution-state NMR spectroscopy., Patzelt H, Simon B, terLaak A, Kessler B, Kuhne R, Schmieder P, Oesterhelt D, Oschkinat H, Proc Natl Acad Sci U S A. 2002 Jul 23;99(15):9765-70. Epub 2002 Jul 15. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/12119389 12119389]
[[Category: Halobacterium salinarum]]
[[Category: Single protein]]
[[Category: Kessler, B.]]
[[Category: Kuhne, R.]]
[[Category: Oesterhaelt, D.]]
[[Category: Oschkinat, H.]]
[[Category: Patzelt, H.]]
[[Category: Schmieder, P.]]
[[Category: Simon, B.]]
[[Category: terLaak, A.]]
[[Category: haloarchaea]]
[[Category: membrane protein]]
[[Category: nmr]]
[[Category: photoreceptor]]
[[Category: proton pump]]
[[Category: proton transport]]
[[Category: retinal protein]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 23:22:23 2008''