1pss

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spinqualitylabelsall models 1pss, resolution 3.0Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTALLOGRAPHIC ANALYSES OF SITE-DIRECTED MUTANTS OF THE PHOTOSYNTHETIC REACTION CENTER FROM RHODOBACTER SPHAEROIDES

Overview

Seven site-directed mutants of the bacterial photosynthetic reaction, center (RC) from the 2.4.1 and WS 231 wild-type strains of Rhodobacter, sphaeroides have been crystallized and their X-ray diffraction analyzed to, resolutions between 3.0 and 4.0 A. The mutations can be divided into four, distinct categories: (1) mutations altering cofactor composition that, affect electron transfer and quantum yield, His M202-->Leu (M202HL), His, L173-->Leu (L173HL), and Leu M214-->His (M214LH); (2) a mutation in the, proposed pathway of electron transfer altering electron-transfer kinetics, Tyr M210-->Phe (M210YF); (3) a mutation around the non-heme iron resulting, in an iron-less reaction center, His M219-->Cys (M219HC); and (4), mutations around the secondary electron acceptor, a ubiquinone, affecting, proton transfer and quinone turnover, Glu L212-->Gln (L212EQ) and Asp, L213-->Asn (L213DN). Residues L173 and M202 are within bonding distance of, the respective magnesiums of the two bacteriochlorophylls of the BChl, special pair, while M214 is close to the bacteriopheophytin on the active, A branch of the RC. The L173HL and M202HL crystal structures show that the, respective bacteriochlorophylls are replaced with bacteriopheophytins, (i.e., loss of magnesium) without significant structural perturbations to, the surrounding main-chain or side-chain atoms. In the M214LH mutant, the, bacteriopheophytin has been replaced by a bacteriochlorophyll, and the, side chain of His M214 is within ligand distance of the magnesium. The, M210YF, L212EQ, and L213DN mutants show no significant tertiary structure, changes near the mutation sites. The M219HC diffraction data indicate that, the overall tertiary structure of the reaction center is maintained in the, absence of the non-heme iron.

About this Structure

1PSS is a Protein complex structure of sequences from Rhodobacter sphaeroides with FE, BCL, BPH, U10 and CRT as ligands. Full crystallographic information is available from OCA.

Reference

Crystallographic analyses of site-directed mutants of the photosynthetic reaction center from Rhodobacter sphaeroides., Chirino AJ, Lous EJ, Huber M, Allen JP, Schenck CC, Paddock ML, Feher G, Rees DC, Biochemistry. 1994 Apr 19;33(15):4584-93. PMID:8161514

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