1e14

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spinqualitylabelsall models 1e14, resolution 2.7Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

PHOTOSYNTHETIC REACTION CENTER MUTANT WITH PHE M197 REPLACED WITH ARG (CHAIN M, FM197R) AND GLY M203 REPLACED WITH ASP (CHAIN M, GM203D)

Overview

Reaction centers with the double mutation Phe M197 to Arg and Gly M203 to, Asp (FM197R/GM203D) have been crystallized from an antenna-deficient, strain of Rhodobacter sphaeroides, and the structure has been determined, at 2.7 A resolution. Unlike in reaction centers with a single FM197R, mutation, the Arg M197 residue in the FM197R/GM203D reaction center adopts, a position similar to that of the native Phe residue in the wild-type, reaction center. Asp M203 is packed in such a way that the gamma-carboxy, group interacts with the backbone carbonyl of Arg M197. The Asp M203, residue takes up part of the volume that is occupied in the wild-type, reaction center by a water molecule. This water has been proposed to form, a hydrogen bond interaction with the 9-keto carbonyl group of the active, branch accessory bacteriochlorophyll, particularly when the primary donor, bacteriochlorophylls are oxidized. The GM203D mutation therefore appears, to remove the possibility of this hydrogen bond interaction by exclusion, of this water molecule, as well as altering the local dielectric, environment of the 9-keto carbonyl group. We examine whether the observed, structural changes can provide new or alternative explanations for the, absorbance and electron-transfer properties of reaction centers with the, FM197R and GM203D mutations.

About this Structure

1E14 is a Protein complex structure of sequences from Rhodobacter sphaeroides with FE, BCL, BPH, U10, SPN, LDA and CDL as ligands. Full crystallographic information is available from OCA.

Reference

Structural consequences of the replacement of glycine M203 with aspartic acid in the reaction center from Rhodobacter sphaeroides., Fyfe PK, Ridge JP, McAuley KE, Cogdell RJ, Isaacs NW, Jones MR, Biochemistry. 2000 May 23;39(20):5953-60. PMID:10821666

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