1jgj: Difference between revisions

[[Image:1jgj.gif|left|200px]]<br /><applet load="1jgj" size="350" color="white" frame="true" align="right" spinBox="true"  

We report an atomic-resolution structure for a sensory member of the microbial rhodopsin family, the phototaxis receptor sensory rhodopsin II (NpSRII), which mediates blue-light avoidance by the haloarchaeon Natronobacterium pharaonis. The 2.4 angstrom structure reveals features responsible for the 70- to 80-nanometer blue shift of its absorption maximum relative to those of haloarchaeal transport rhodopsins, as well as structural differences due to its sensory, as opposed to transport, function. Multiple factors appear to account for the spectral tuning difference with respect to bacteriorhodopsin: (i) repositioning of the guanidinium group of arginine 72, a residue that interacts with the counterion to the retinylidene protonated Schiff base; (ii) rearrangement of the protein near the retinal ring; and (iii) changes in tilt and slant of the retinal polyene chain. Inspection of the surface topography reveals an exposed polar residue, tyrosine 199, not present in bacteriorhodopsin, in the middle of the membrane bilayer. We propose that this residue interacts with the adjacent helices of the cognate NpSRII transducer NpHtrII.

1JGJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Natronomonas_pharaonis Natronomonas pharaonis] with <scene name='pdbligand=BOG:'>BOG</scene> and <scene name='pdbligand=RET:'>RET</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. The following page contains interesting information on the relation of 1JGJ with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb27_1.html Bacteriorhodopsin]]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JGJ OCA].  

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