1dv3

[[Image:1dv3.gif|left|200px]]

|PDB= 1dv3 |SIZE=350|CAPTION= <scene name='initialview01'>1dv3</scene>, resolution 2.50&Aring;

|SITE=

|LIGAND= <scene name='pdbligand=BCL:BACTERIOCHLOROPHYLL+A'>BCL</scene>, <scene name='pdbligand=BPH:BACTERIOPHEOPHYTIN+A'>BPH</scene>, <scene name='pdbligand=CD:CADMIUM+ION'>CD</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=FE2:FE+(II)+ION'>FE2</scene>, <scene name='pdbligand=LDA:LAURYL+DIMETHYLAMINE-N-OXIDE'>LDA</scene>, <scene name='pdbligand=U10:UBIQUINONE-10'>U10</scene>

|ACTIVITY=

|GENE=

|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1dv3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1dv3 OCA], [http://www.ebi.ac.uk/pdbsum/1dv3 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1dv3 RCSB]</span>

 

 

 

==Overview==

The reaction center (RC) from Rhodobacter sphaeroides couples light-driven electron transfer to protonation of a bound quinone acceptor molecule, Q(B), within the RC. The binding of Cd(2+) or Zn(2+) has been previously shown to inhibit the rate of reduction and protonation of Q(B). We report here on the metal binding site, determined by x-ray diffraction at 2.5-A resolution, obtained from RC crystals that were soaked in the presence of the metal. The structures were refined to R factors of 23% and 24% for the Cd(2+) and Zn(2+) complexes, respectively. Both metals bind to the same location, coordinating to Asp-H124, His-H126, and His-H128. The rate of electron transfer from Q(A)(-) to Q(B) was measured in the Cd(2+)-soaked crystal and found to be the same as in solution in the presence of Cd(2+). In addition to the changes in the kinetics, a structural effect of Cd(2+) on Glu-H173 was observed. This residue was well resolved in the x-ray structure-i.e., ordered-with Cd(2+) bound to the RC, in contrast to its disordered state in the absence of Cd(2+), which suggests that the mobility of Glu-H173 plays an important role in the rate of reduction of Q(B). The position of the Cd(2+) and Zn(2+) localizes the proton entry into the RC near Asp-H124, His-H126, and His-H128. Based on the location of the metal, likely pathways of proton transfer from the aqueous surface to Q(B) are proposed.

 

==About this Structure==

1DV3 is a [[Protein complex]] structure of sequences from [http://en.wikipedia.org/wiki/Rhodobacter_sphaeroides Rhodobacter sphaeroides]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1DV3 OCA].

 

Determination of the binding sites of the proton transfer inhibitors Cd2+ and Zn2+ in bacterial reaction centers., Axelrod HL, Abresch EC, Paddock ML, Okamura MY, Feher G, Proc Natl Acad Sci U S A. 2000 Feb 15;97(4):1542-7. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/10677497 10677497]

[[Category: Protein complex]]

[[Category: Rhodobacter sphaeroides]]

[[Category: Abresch, E C.]]

[[Category: Axelrod, H L.]]

[[Category: Feher, G.]]

[[Category: Okamura, M Y.]]

[[Category: Paddock, M L.]]