2JJ0

PHOTOSYNTHETIC REACTION CENTER MUTANT WITH ALA M248 REPLACED WITH TRP (CHAIN M, AM248W)

Summary for 2JJ0

• Entry DOI: 10.2210/pdb2jj0/pdb
• Related: 1AIG 1AIJ 1DS8 1DV3 1DV6 1E14 1E6D 1F6N 1FNP 1FNQ 1JGW 1JGX 1JGY 1JGZ 1JH0 1K6L 1K6N 1KBY 1L9B 1L9J 1M3X 1MPS 1OGV 1PCR 1PSS 1PST 1QOV 1RG5 1RGN 1RQK 1RVJ 1RY5 1RZH 1RZZ 1S00 1UMX 1YST 1Z9J 1Z9K 2BNP 2BNS 2BOZ 2GMR 2J8C 2J8D 2JIY 2RCR 2UWS 2UWT 2UWU 2UWV 2UWW 2UX3 2UX4 2UX5 2UXJ 2UXK 2UXL 2UXM 4RCR
• Descriptor: REACTION CENTER PROTEIN H CHAIN, CHLORIDE ION, REACTION CENTER PROTEIN L CHAIN, ... (11 entities in total)
• Functional Keywords: photosynthesis, reaction center, membrane protein, photosynthetic reaction center, electron transport, bacteriochlorophyll, chlorophyll, metal-binding, transmembrane, iron, membrane, transport, magnesium, chromophore
• Biological source: RHODOBACTER SPHAEROIDES; More
• Cellular location: Cellular chromatophore membrane; Single-pass membrane protein: P0C0Y7; Cellular chromatophore membrane; Multi-pass membrane protein: P0C0Y8 P0C0Y9
• Total number of polymer chains: 3
• Total formula weight: 102495.70

Authors

Fyfe, P.K.,Potter, J.A.,Cheng, J.,Williams, C.M.,Watson, A.J.,Jones, M.R. (deposition date: 2007-07-03, release date: 2007-09-04, Last modification date: 2024-05-01)

Primary citation

Fyfe, P.K.,Potter, J.A.,Cheng, J.,Williams, C.M.,Watson, A.J.,Jones, M.R.
Structural Responses to Cavity-Creating Mutations in an Integral Membrane Protein.
Biochemistry, 46:10461-, 2007

PubMed Abstract: X-ray crystallography has been used to investigate the extent of structural changes in mutants of the purple bacterial reaction center that assemble without a particular ubiquinone or bacteriopheophytin cofactor. In the case of the bacteriopheophytin-exclusion mutant, in which Ala M149 was replaced by Trp (AM149W), the quality of protein crystals was improved over that seen in previous work by minimizing illumination, time, and temperature during the purification protocol and carrying out crystal growth at 4 degrees C after overnight incubation at 18 degrees C. The X-ray crystal structure of the AM149W mutant, determined to a resolution of 2.2 A, showed very little change in protein structure despite the absence of the bacteriopheophytin cofactor. Changes in the electron density map in the region of the cofactor binding site could be accounted for by changes in the conformation of the phytol side chains of adjacent cofactors and the presence of a buried water molecule. Residues lining the vacated binding pocket did not show any significant changes in conformation or increases in disorder as assessed through crystallographic atomic displacement parameters (B-factors). The X-ray crystal structure of a reaction center lacking the primary acceptor ubiquinone through mutation of Ala M248 to Trp (AM248W) was also determined, to a resolution of 2.8 A. Again, despite the absence of an internal cofactor only very minor changes in protein structure were observed. This is in contrast to a previous report on a reaction center lacking this ubiquinone through mutation of Ala M260 to Trp (AM260W) where more extensive changes in structure were apparent. All three mutant reaction centers showed a decrease in thermal stability when housed in the native membrane, but this decrease was smaller for the AM260W mutant than the AM248W complex, possibly due to beneficial effects of the observed changes in protein structure. The lack of major changes in protein structure despite the absence of large internal cofactors is discussed in terms of protein rigidity, the protective influence of the adaptable membrane environment, and the role of small molecules and ions as packing material in the internal cavities created by this type of mutation.

PubMed: 17711306
DOI: 10.1021/BI701085W

Experimental method

X-RAY DIFFRACTION (2.8 Å)