1UMX

PHOTOSYNTHETIC REACTION CENTER MUTANT WITH ARG M267 REPLACED WITH LEU (CHAIN M, R267L)

Summary for 1UMX

• Entry DOI: 10.2210/pdb1umx/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 1YST 2RCR 4RCR
• Descriptor: REACTION CENTER PROTEIN H CHAIN, PHOSPHATE ION, REACTION CENTER PROTEIN L CHAIN, ... (11 entities in total)
• Functional Keywords: photosynthetic reaction center, transmembrane, electron transport, photosynthesis, cardiolipin, membrane protein
• Biological source: RHODOBACTER SPHAEROIDES; More
• Total number of polymer chains: 3
• Total formula weight: 101255.59

Authors

Fyfe, P.K.,Isaacs, N.W.,Cogdell, R.J.,Jones, M.R. (deposition date: 2003-09-02, release date: 2004-06-29, Last modification date: 2024-05-01)

Primary citation

Fyfe, P.K.,Isaacs, N.W.,Cogdell, R.J.,Jones, M.R.
Disruption of a specific molecular interaction with a bound lipid affects the thermal stability of the purple bacterial reaction centre.
Biochim.Biophys.Acta, 1608:11-22, 2004

PubMed Abstract: Relatively little is known about the functions of specific molecular interactions between membrane proteins and membrane lipids. The structural and functional consequences of disrupting a previously identified interaction between a molecule of the diacidic lipid cardiolipin and the purple bacterial reaction centre were examined. Mutagenesis of a highly conserved arginine (M267) that is responsible for binding the head-group of the cardiolipin (to leucine) did not affect the rate of photosynthetic growth, the functional properties of the reaction centre, or the X-ray crystal structure of the complex (determined to a resolution of 2.8 A). However, the thermal stability of the protein was compromised by this mutation, part of the reaction centre population showing an approximately 5 degrees C decrease in melting temperature in response to the arginine to leucine mutation. The crystallised mutant reaction centre also no longer bound detectable amounts of cardiolipin at this site. Taken together, these observations suggest that this particular protein-lipid interaction contributes to the thermal stability of the complex, at least when in detergent micelles. These findings are discussed in the light of proposals concerning the unfolding processes that occur when membrane proteins are heated, and we propose that one function of the cardiolipin is to stabilise the interaction between adjacent membrane-spanning alpha-helices in a region where there are no direct protein-protein interactions.

PubMed: 14741581
DOI: 10.1016/j.bbabio.2003.09.014

Experimental method

X-RAY DIFFRACTION (2.8 Å)