The association of different detergents with the photosynthetic reaction center protein of Rhodobacter sphaeroides R26 and the effects on its photochemistry

Detergent-free reaction centers from Rhodobacter sphaeroides R26 were used to study the solubilization of reaction centers in various detergents and their effects on reaction center photochemistry. 500 +/- 100 n-octyl-beta-D-glucopyranoside or 51 +/- 5 Triton X-100 molecules were associated with one reaction center. For N,N-alkylamine N-oxide detergents with chain lengths in the range from 8-13 carbon atoms, the number of detergent molecules associated with the reaction centers increased with decreasing chain length. The amount of detergent molecules associated with the reaction centers decreased almost tenfold if the pH was increased from pH 6 to pH 10, The addition of 5% 1,2,3-heptanetriol to various detergents lowered the detergent/reaction center ratio by a factor of two compared to that fur the pure detergent. The detergent concentration at which solubilization of the reaction center occurs was close to the critical micelle concentration for all detergents studied. The absorption band at 865 nm of the primary donor in the reaction center shifts to 846 nm when detergent was removed from the reaction center; upon resolubilization with various detergents, this band shifts back to 865 nm. In 80-90% of the detergent-free reaction centers, the secondary electron transfer from Q(A) to Q(B) was inhibited; this electron transfer was restored after re-addition of detergent

Viridoxins a and B: Novel Toxins From the Fungus, Metarhizium Flavoviridae

Abstract. Relational methods are gaining growing acceptance for specifying and verifying properties defined in terms of the execution of two programs—notions such as simulation, observational equivalence, non-interference, and continuity can be elegantly casted in this setting. In previous work, we have proposed program product construction as a technique to reduce relational verification to standard verification. This method hinges on the ability to interpret relational assertions as traditional predicates, which becomes problematic when considering assertions from relational separation logic. We report in this article an alternative method that overcomes this difficulty, defined as a relational weakest precondition calculus based on separation logic and formalized in the Coq proof assistant. The formalization includes an application to the formal verification of the Schorr-Waite graph marking algorithm. We discuss additional variants of relational separation logic inspired by the standard notions of partial and total correctness, and extensions of the logic to handle non-structurally equivalent programs.