Spectroscopic studies of the AppA BLUF domain from Rhodobacter sphaeroides: addressing movement of tryptophan 104 in the signaling state.

ABSTRACT: Previous crystallographic studies of the AppA BLUF domain indicated that Trp104 is capable of undertaking alternate conformations depending on the length of the BLUF domain. A BLUF domain containing a C-terminal deletion (AppA1-126) reveals that Trp104 is partially solvent exposed while a BLUF domain containing a slightly longer carboxyl terminal region (AppA17-133) shows that Trp104 is deeply buried. This observation has led to a model proposing that Trp104 moves from a deeply buried position in the dark state to a solvent-exposed position in the light excited state. In this study we investigated whether there is indeed movement of Trp104 upon light excitation using a combination of NMR and absorption spectroscopy, steady-state fluorescence, and acrylamide quenching of tryptophan fluoresc

SUBMITTER: Dragnea V 

PROVIDER: S-EPMC2774281 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature