1f4z: Difference between revisions

Revision as of 15:54, 2 May 2008

BACTERIORHODOPSIN-M PHOTOINTERMEDIATE STATE OF THE E204Q MUTANT AT 1.8 ANGSTROM RESOLUTION

OverviewOverview

In order to understand how isomerization of the retinal drives unidirectional transmembrane ion transport in bacteriorhodopsin, we determined the atomic structures of the BR state and M photointermediate of the E204Q mutant, to 1.7 and 1.8 A resolution, respectively. Comparison of this M, in which proton release to the extracellular surface is blocked, with the previously determined M in the D96N mutant indicates that the changes in the extracellular region are initiated by changes in the electrostatic interactions of the retinal Schiff base with Asp85 and Asp212, but those on the cytoplasmic side originate from steric conflict of the 13-methyl retinal group with Trp182 and distortion of the pi-bulge of helix G. The structural changes suggest that protonation of Asp85 initiates a cascade of atomic displacements in the extracellular region that cause release of a proton to the surface. The progressive relaxation of the strained 13-cis retinal chain with deprotonated Schiff base, in turn, initiates atomic displacements in the cytoplasmic region that cause the intercalation of a hydrogen-bonded water molecule between Thr46 and Asp96. This accounts for the lowering of the pK(a) of Asp96, which then reprotonates the Schiff base via a newly formed chain of water molecules that is extending toward the Schiff base.

About this StructureAbout this Structure

1F4Z is a Single protein structure of sequence from Halobacterium salinarum. Full crystallographic information is available from OCA.

ReferenceReference

Coupling photoisomerization of retinal to directional transport in bacteriorhodopsin., Luecke H, Schobert B, Cartailler JP, Richter HT, Rosengarth A, Needleman R, Lanyi JK, J Mol Biol. 2000 Jul 28;300(5):1237-55. PMID:10903866 Page seeded by OCA on Fri May 2 15:54:24 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

@@ Line 1: / Line 1: @@
 [[Image:1f4z.jpg|left|200px]]
- {{Structure
+<!--
-|PDB= 1f4z |SIZE=350|CAPTION= <scene name='initialview01'>1f4z</scene>, resolution 1.80&Aring;
+The line below this paragraph, containing "STRUCTURE_1f4z", creates the "Structure Box" on the page.
-|SITE=
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=LI1:1-[2,6,10.14-TETRAMETHYL-HEXADECAN-16-YL]-2-[2,10,14-TRIMETHYLHEXADECAN-16-YL]GLYCEROL'>LI1</scene>, <scene name='pdbligand=RET:RETINAL'>RET</scene>, <scene name='pdbligand=SQU:2,10,23-TRIMETHYL-TETRACOSANE'>SQU</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY=
+or leave the SCENE parameter empty for the default display.
-|GENE=
+-->
-|DOMAIN=
+{{STRUCTURE_1f4z|  PDB=1f4z  |  SCENE=  }}
-|RELATEDENTRY=[[1c3w|1C3W]], [[1c8r|1C8R]], [[1c8s|1C8S]], [[1f50|1f50]]
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1f4z FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f4z OCA], [http://www.ebi.ac.uk/pdbsum/1f4z PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1f4z RCSB]</span>
-}}
 '''BACTERIORHODOPSIN-M PHOTOINTERMEDIATE STATE OF THE E204Q MUTANT AT 1.8 ANGSTROM RESOLUTION'''
@@ Line 33: / Line 30: @@
 [[Category: Schobert, B.]]
 [[Category: 7-transmembrane]]
-[[Category: e204q mutant m state]]
+[[Category: E204q mutant m state]]
-[[Category: haloarchaea]]
+[[Category: Haloarchaea]]
-[[Category: ion pump]]
+[[Category: Ion pump]]
-[[Category: ion transport]]
+[[Category: Ion transport]]
-[[Category: lipid]]
+[[Category: Lipid]]
-[[Category: membrane protein]]
+[[Category: Membrane protein]]
-[[Category: merohedral twinning]]
+[[Category: Merohedral twinning]]
-[[Category: photocycle intermediate]]
+[[Category: Photocycle intermediate]]
-[[Category: photoreceptor]]
+[[Category: Photoreceptor]]
-[[Category: retinal protein]]
+[[Category: Retinal protein]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 15:54:24 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 20:15:57 2008''