Structural dynamics of blue light sensitive bacterial photoreceptor blsA

B lue l ight s ensing A (blsA) is a b lue l ight u sing f lavin (BLUF) domain isolated from opportunistic pathogen Acinetobacter baumanii. BlsA is vital for A. baumanii’ s motility, biofilm formation and virulence. When blue light activates blsA [in the N‐terminus], the protein interacts with its effector domain(s) [in the C‐terminus] with implications in downstream signaling events. Photo absorption modifies the hydrogen bonds and the electrostatic interactions between flavin and the BLUF domain with consequent structural changes that are integral in the signal transduction. Spectroscopic data highlight involvement of residues glutamine (51) and tryptophan (92) in the photoactivated signaling state of blsA. My goal is to solve blsA's structure using x‐ray crystallography to determine the specific residues involved in the signaling state. Comparison of crystal structures of blsA (~1.8 Å) in the dark state and the photoactivated light state does not show movement of the residues glutamine and tryptophan in the two states. However, we detect a distinct conformational change of an alpha‐helix in the C‐terminus‐ the effector protein binding terminus‐ of blsA. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .