The effect of internal voids in membrane proteins: high-pressure study of two photochemical reaction centres from Rhodobacter sphaeroides.
The effect of application of high pressure on the carotenoid-containing bacterial reaction centre from Rhodobacter sphaeroides strain 2.4.1 was studied, and compared to recent experiments performed on its carotenoid-less counterpart, isolated from strain R26.1. Our results indicate that the cavity created by the absence of carotenoid contributes to localised differences in protein compressibility when using the intrinsic chromophores as molecular probes. Differential stability of the electronic transitions of the primary electron donor under high hydrostatic pressure is observed, dependent on the presence of the carotenoid cofactor. This suggests that the transition intensity loss is induced by a slight change of the primary electron donor structure, allowed by the void created by the absence of the carotenoid molecule.
Service de Biophysique des Fonctions Membranaires, DBJC/CEA and URA CNRS 2096, CEA-Saclay, 91191 Gif-sur-Yvette Cedex, France. andrew.gall@bio.gla.ac.uk
Andrew
A
Gall
Aleksandr
A
Ellervee
Bruno
B
Robert
Arvi
A
Freiberg
D001429:Bacteriochlorophylls / Q000737:chemistry; D004548:Elasticity; D008565:Membrane Proteins / Q000737:chemistry*; D015335:Molecular Probes; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011312:Pressure; D011487:Protein Conformation; D012242:Rhodobacter sphaeroides / Q000378:metabolism*; D013053:Spectrophotometry; D013059:Spectrum Analysis, Raman
D001429:Bacteriochlorophylls; D008565:Membrane Proteins; D015335:Molecular Probes; D045322:Photosynthetic Reaction Center Complex Proteins