1dxr
From Proteopedia
Photosynthetic reaction center from Rhodopseudomonas viridis - His L168 Phe mutant (terbutryn complex)
Structural highlights
Function[RCEM_RHOVI] The reaction center is a membrane-bound complex that mediates the initial photochemical event in the electron transfer process of photosynthesis. [CYCR_RHOVI] The reaction center of purple bacteria contains a tightly bound cytochrome molecule which re-reduces the photo oxidized primary electron donor. [RCEL_RHOVI] The reaction center is a membrane-bound complex that mediates the initial photochemical event in the electron transfer process of photosynthesis. [RCEH_RHOVI] The reaction center is a membrane-bound complex that mediates the initial photochemical event in the electron transfer process of photosynthesis. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedIt has previously been shown that replacement of the residue His L168 with Phe (HL168F) in the Rhodopseudomonas viridis reaction center (RC) leads to an unprecedented drastic acceleration of the initial electron transfer rate. Here we describe the determination of the x-ray crystal structure at 2.00-A resolution of the HL168F RC. The electron density maps confirm that a hydrogen bond from the protein to the special pair is removed by this mutation. Compared with the wild-type RC, the acceptor of this hydrogen bond, the ring I acetyl group of the "special pair" bacteriochlorophyll, D(L), is rotated, and its acetyl oxygen is found 1.1 A closer to the bacteriochlorophyll-Mg(2+) of the other special pair bacteriochlorophyll, D(M). The rotation of this acetyl group and the increased interaction between the D(L) ring I acetyl oxygen and the D(M)-Mg(2+) provide the structural basis for the previously observed 80-mV decrease in the D(+)/D redox potential and the drastically increased rate of initial electron transfer to the accessory bacteriochlorophyll, B(A). The high quality of the electron density maps also allowed a reliable discussion of the mode of binding of the triazine herbicide terbutryn at the binding site of the secondary quinone, Q(B). Structural basis of the drastically increased initial electron transfer rate in the reaction center from a Rhodopseudomonas viridis mutant described at 2.00-A resolution.,Lancaster CR, Bibikova MV, Sabatino P, Oesterhelt D, Michel H J Biol Chem. 2000 Dec 15;275(50):39364-8. PMID:11005826[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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