title: The asymmetry of P+ in bacterial reaction centers revealed by circular dichroism spectroscopy.
abstract: The circular dichroism anisotropy, (AL-AR)/A, has been measured for the far-red absorption band of P+ in reaction centers of two purple bacteria (Rhodopseudomonas viridis and Rhodobacter sphaerides) and one green sulfur bacterium (Chlorobium tepidum). The anisotropy values for P960+ (Rps. virdis) at 1310 nm was found to be +(13 +/- 2) x 10(-4). The corresponding for P870+ (Rb. sphaeroides) at 1250 nm was +(11 +/- 1) x 10(-4), but for P840+ (C. tepdium) at 1160 nm the value was negative: -(27 +/- 2) x 10(-4). These results show that the configuration of the special pair in P840 is significantly different from the configuration in P870 and P960.
authors.affiliation: Institute of Biochemistry, Odense University, Denmark.
authors.forename: J M
authors.initials: JM
authors.lastname: Olson
authors.forename: M
authors.initials: M
authors.lastname: Miller
authors.forename: J
authors.initials: J
authors.lastname: D'Olieslager
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology; D001419:Bacteria / Q000737:chemistry*; D002942:Circular Dichroism; D005292:Ferricyanides / Q000494:pharmacology; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D012242:Rhodobacter sphaeroides / Q000737:chemistry*; D012241:Rhodopseudomonas / Q000737:chemistry*; D013053:Spectrophotometry
chemical_list: D005292:Ferricyanides; D045322:Photosynthetic Reaction Center Complex Proteins; D001205:Ascorbic Acid; C028033:potassium ferricyanide