The uptake of 4-chlorobenzoate (4-CBA) in intact cells of the coryneform bacterium NTB-1 was investigated. Uptake and metabolism of 4-CBA were observed in cells grown in 4-CBA but not in glucose-grown cells. Under aerobic conditions, uptake of 4-CBA occurred with a high apparent affinity (apparent Kt, 1.7 microM) and a maximal velocity (Vmax) of 5.1 nmol min-1 mg of protein-1. At pH values belo...

Electron transporting (n-type) polymers are the coveted complementary counterpart to more thoroughly studied hole (p-type) semiconducting polymers. Besides intrinsic stability issues of doped form n-type polymer toward ubiquitous oxidizing agents (H2O and O2), choice suitable n-dopants underlying mechanism doping is an open research field. Using a low LUMO, unipolar acceptor1-acceptor2 copolyme...

Thermally activated delayed fluorescence (TADF) materials have shown great potential for highly efficient organic light-emitting diodes (OLEDs). While the current molecular design of TADF materials primarily focuses on combining donor and acceptor units, we present a novel system based on the use of excited-state intramolecular proton transfer (ESIPT) to achieve efficient TADF without relying o...

Synthesis and characterization of a novel type of ambident bridging ligands joining together the functional prerequisites for visible-light absorption, photoinduced electron transfer and catalytic proton reduction is presented. This class of compounds consists of a chromophoric 1,2-diimine-based π-acceptor site and a rigid polyaromatic dithiolate chelator. Due to the presence of a common conjug...

Carboxylic acids are ubiquitous in bio-renewable and petrochemical sources of carbon. Hydrogenation of carboxylic acids to yield alcohols produces water as the only byproduct, and thus represents a possible next generation, sustainable method for the production of these alternative energy carriers/platform chemicals on a large scale. Reported herein are molecular insights into cationic mononucl...

Clostridium thermocellum polynucleotide kinase (CthPnk), the 50 end-healing module of a bacterial RNA repair system, catalyzes reversible phosphoryl transfer from an NTP donor to a 50-OH polynucleotide acceptor. Here we report the crystal structures of CthPnk-D38N in a Michaelis complex with GTP Mg and a 50-OH oligonucleotide and a product complex with GDP Mgand a 5-PO4 oligonucleotide. The O50...

The origin of O-H vibrational red-shifts observed experimentally in (H2O)n(-) clusters is analyzed using electronic structure calculations, including natural bond orbital analysis. The red-shifts are shown to arise from significant charge transfer and strong donor-acceptor stabilization between the unpaired electron and O-H sigma* orbitals on a nearby water molecule in a double hydrogen-bond-ac...

Clostridium thermocellum polynucleotide kinase (CthPnk), the 5' end-healing module of a bacterial RNA repair system, catalyzes reversible phosphoryl transfer from an NTP donor to a 5'-OH polynucleotide acceptor. Here we report the crystal structures of CthPnk-D38N in a Michaelis complex with GTP•Mg(2+) and a 5'-OH oligonucleotide and a product complex with GDP•Mg(2+) and a 5'-PO4 oligonucleotid...

We report investigations of resonance energy transfer in the green fluorescent protein and calmodulin-based fluorescent indicator constructs for Ca(2+) called cameleons using steady-state and time-resolved spectroscopy of the full construct and of the component green fluorescent protein mutants, namely ECFP (donor) and EYFP (acceptor). EYFP displays a complicated photophysical behavior includin...

Homologous to bacteriorhodopsin and even more to proteorhodopsin, xanthorhodopsin is a light-driven proton pump that, in addition to retinal, contains a noncovalently bound carotenoid with a function of a light-harvesting antenna. We determined the structure of this eubacterial membrane protein-carotenoid complex by X-ray diffraction, to 1.9-A resolution. Although it contains 7 transmembrane he...