1dxr

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spinqualitylabelsall models 1dxr, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

PHOTOSYNTHETIC REACTION CENTER FROM RHODOPSEUDOMONAS VIRIDIS-HIS L168 PHE MUTANT (TERBUTRYN COMPLEX)

Overview

It 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).

About this Structure

1DXR is a Protein complex structure of sequences from Blastochloris viridis with FE2, SO4, HEC, BCB, BPB, MQ9, MST, NS5 and LDA as ligands. Full crystallographic information is available from OCA.

Reference

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

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