A Combination of Library Screening and Rational Mutagenesis Expands the Available Color Palette of the Smallest Fluorogen-Activating Protein Tag nanoFAST.

NanoFAST is the smallest fluorogen-activating protein, consisting of only 98 amino acids, used as a genetically encoded fluorescent tag. Previously, only a single fluorogen with an orange color was revealed for this protein. In the present paper, using rational mutagenesis and in vitro screening of fluorogens libraries, we expanded the color palette of this tag.

Meta-CF-Substituted Analogues of the GFP Chromophore with Remarkable Solvatochromism.

In this work, we have shown that the introduction of a trifluoromethyl group into the me-ta-position of arylidene imidazolones (GFP chromophore core) leads to a dramatic increase in their fluorescence in nonpolar and aprotic media. The presence of a pronounced solvent-dependent gradation of fluorescence intensity makes it possible to use these substances as fluorescent polarity sensors. In particular, we showed that one of the created compounds could be used for selective labeling of the endoplasmic reticulum of living cells.

Total Synthesis of Racemic Thieno[3,2-]thiochromene Tricarboxylate, a Luciferin from Marine Polychaeta .

We report the first total synthesis of racemic luciferin, a thieno[3,2-]thiochromene tricarboxylate comprising a 6-6-5-fused tricyclic skeleton with three sulfur atoms in different electronic states. The key transformation is based on tandem condensation of bifunctional thiol-phosphonate, obtained from dimethyl acetylene dicarboxylate, with benzothiophene-6,7-quinone. The presented convergent approach provides the synthesis of the target compound with a previously unreported fused heterocyclic core in 11 steps, thus allowing for unambiguous confirmation of the chemical structure of luciferin by 2D-NMR spectroscopy.

Bioluminescence chemistry of fireworm .

Marine polychaetes , commonly known as fireworms, emit bright blue-green bioluminescence. Until the recent identification of the luciferase enzyme, little progress had been made toward characterizing the key components of this bioluminescence system. Here we present the biomolecular mechanisms of enzymatic (leading to light emission) and nonenzymatic (dark) oxidation pathways of newly described luciferin.

Proton-independent activation of acid-sensing ion channel 3 by an alkaloid, lindoldhamine, from Laurus nobilis.

Background And Purpose: Acid-sensing ion channels (ASICs) play an important role in synaptic plasticity and learning, as well as in nociception and mechanosensation. ASICs are involved in pain and in neurological and psychiatric diseases, but their therapeutic potential is limited by the lack of ligands activating them at physiological pH.

Experimental Approach: We extracted, purified and determined the structure of a bisbenzylisoquinoline alkaloid, lindoldhamine, (LIN) from laurel leaves.

A novel type of luciferin from the Siberian luminous earthworm Fridericia heliota: structure elucidation by spectral studies and total synthesis.

The structure elucidation and synthesis of the luciferin from the recently discovered luminous earthworm Fridericia heliota is reported. This luciferin is a key component of a novel ATP-dependent bioluminescence system. UV, fluorescence, NMR, and HRMS spectroscopy studies were performed on 0.