Light-induced chromophore activity and signal transduction in phytochromes observed by 13C and 15N magic-angle spinning NMR.

ABSTRACT: Both thermally stable states of phytochrome, Pr and Pfr, have been studied by (13)C and (15)N cross-polarization (CP) magic-angle spinning (MAS) NMR using cyanobacterial (Cph1) and plant (phyA) phytochrome sensory modules containing uniformly (13)C- and (15)N-labeled bilin chromophores. Two-dimensional homo- and heteronuclear experiments allowed most of the (13)C chemical shifts to be assigned in both states. Chemical shift differences reflect changes of the electronic structure of the cofactor at the atomic level as well as its interactions with the chromophore-binding pocket. The chromophore in cyanobacterial and plant phytochromes shows very similar features in the respective Pr and Pfr states. The data are interpreted in terms of a strengthened hydrogen bond at the ring D carbonyl. The

SUBMITTER: Rohmer T 

PROVIDER: S-EPMC2563065 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature