title: Determination of the number of detergent molecules associated with the reaction center protein isolated from the photosynthetic bacterium Rhodopseudomonas viridis. Effects of the amphiphilic molecule 1,2,3-heptanetriol.
abstract: Detergent-free reaction center (RC) proteins from the photosynthetic bacterium Rhodopseudomonas viridis were obtained using Bio-Beads SM-2. With these RCs, the amount of detergent molecules associated with the protein was measured by determining the detergent concentration at which re-solubilization occurred as a function of the RC concentration. For N,N-dimethyl dodecylamine-N-oxide (LDAO), Triton X-100 and beta-octylglucoside 260 +/- 30,105 +/- 10 and 360 +/- 100 detergent molecules were necessary to dissolve the protein, respectively. With this technique we have studied the effect of the amphiphilic molecule 1,2,3-heptanetriol, which is essential in the crystallization process of these RCs. Addition of 5% 1,2,3-heptanetriol reduces the value for LDAO to 120 +/- 20 LDAO/RC, supporting the notion that crystallization of the RCs is promoted by increasing the number of protein-protein contacts.
authors.affiliation: Department of Biophysics, Huygens Laboratory, Leiden, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: Gast
authors.forename: P
authors.initials: P
authors.lastname: Hemelrijk
authors.forename: A J
authors.initials: AJ
authors.lastname: Hoff
mesh_terms: D003460:Crystallization; D003902:Detergents / Q000032:analysis*; D004123:Dimethylamines / Q000032:analysis / Q000494:pharmacology; D005233:Fatty Alcohols / Q000494:pharmacology*; D005960:Glucosides / Q000032:analysis / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D017830:Octoxynol / Q000032:analysis / Q000494:pharmacology; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D012241:Rhodopseudomonas / Q000737:chemistry*; D012995:Solubility
chemical_list: D003902:Detergents; D004123:Dimethylamines; D005233:Fatty Alcohols; D005960:Glucosides; D045322:Photosynthetic Reaction Center Complex Proteins; C068115:heptane-1,2,3-triol; C018619:octyl-beta-D-glucoside; C014518:dodecyldimethylamine oxide; D017830:Octoxynol