BLUF domains (sensors of blue light using flavin adenine dinucleotide) are a group of flavin-containing blue light photosensory domains from a variety of bacterial and algal proteins. While spectroscopic studies have indicated that these domains reorganize their interactions with an internally bound chromophore upon illumination, it remains unclear how these are converted into structural and functional changes. To address this, we have solved the solution structure of the BLUF domain from Klebsiella pneumoniae BlrP1, a light-activated c-di-guanosine 5'-monophosphate phosphodiesterase which consists of a sensory BLUF and a catalytic EAL (Glu-Ala-Leu) domain [Schmidt et. al. (2008) J. Bacteriol. 187, 4774-4781]. Our dark state structure of the sensory domain shows that it adopts a standard BLUF domain fold followed by two C-terminal alpha helices which adopt a novel orientation with respect to the rest of the domain. Comparison of NMR spectra acquired under dark and light conditions suggests that residues throughout the BlrP1 BLUF domain undergo significant light-induced chemical shift changes, including sites clustered on the beta(4)beta(5) loop, beta(5) strand, and alpha(3)alpha(4) loop. Given that these changes were observed at several sites on the helical cap, over 15 A from chromophore, our data suggest a long-range signal transduction process in BLUF domains.
", 2001 ; Yuan et al . , 2006 ; Wu and Gardner , 2009 ) . Despite these initial achievements in unraveling signal - transduction pathways , several major questions regarding these secondary steps in photoreception remain unanswered : Up to now , the interaction between individual multi - domain photoreceptors ( e . "
[Show abstract][Hide abstract] ABSTRACT: Electron paramagnetic resonance (EPR) spectroscopy is a well-established spectroscopic method for the examination of paramagnetic molecules. Proteins can contain paramagnetic moieties in form of stable cofactors, transiently formed intermediates, or spin labels artificially introduced to cysteine sites. The focus of this review is to evaluate potential scopes of application of EPR to the emerging field of optogenetics. The main objective for EPR spectroscopy in this context is to unravel the complex mechanisms of light-active proteins, from their primary photoreaction to downstream signal transduction. An overview of recent results from the family of flavin-containing, blue-light dependent photoreceptors is given. In detail, mechanistic similarities and differences are condensed from the three classes of flavoproteins, the cryptochromes, LOV (Light-oxygen-voltage), and BLUF (blue-light using FAD) domains. Additionally, a concept that includes spin-labeled proteins and examination using modern pulsed EPR is introduced, which allows for a precise mapping of light-induced conformational changes.
Frontiers in Bioscience 10/2015; 2. DOI:10.3389/fmolb.2015.00049 · 3.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Network technology, multimedia applications and digital devices
have become ubiquitous in our society. Most people have their own
information appliances and can easily access various types of
information. Big changes are occurring everywhere: in our offices,
homes, cars and so on. Unfortunately, the human capacity for processing
information is limited. Coping with the mass of information with which
we are faced is impossible. Systems must, therefore, estimate users'
cognitive loads and make judgements about the most suitable combination
of media, modality and the intrusiveness with which information is
presented. We propose a basic system architecture that gradually adapts
to individual cognitive capability
Industrial Electronics Society, 2000. IECON 2000. 26th Annual Confjerence of the IEEE; 02/2000
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