BiOCl single-crystalline nanosheets with exposed {001} and {010} facets were selectively synthesized via a facile hydrothermal route. The resulting BiOCl single-crystalline nanosheets with exposed {001} facets exhibited higher activity for direct semiconductor photoexcitation pollutant degradation under UV light, but the counterpart with exposed {010} facets possessed superior activity for indirect dye photosensitization degradation under visible light.

The nucleobase/ascorbate transporter (NAT) proteins, also known as nucleobase/cation symporter 2 (NCS2) proteins, are responsible for the uptake of nucleobases in all kingdoms of life and for the transport of vitamin C in mammals. Despite functional characterization of the NAT family members in bacteria, fungi and mammals, detailed structural information remains unavailable. Here we report the crystal structure of a representative NAT protein, the Escherichia coli uracil/H(+) symporter UraA, in complex with uracil at a resolution of 2.8 Å. UraA has a novel structural fold, with 14 transmembrane segments (TMs) divided into two inverted repeats. A pair of antiparallel β-strands is located between TM3 and TM10 and has an important role in structural organization and substrate recognition. The structure is spatially arranged into a core domain and a gate domain. Uracil, located at the interface between the two domains, is coordinated mainly by residues from the core domain. Structural analysis suggests that alternating access of the substrate may be achieved through conformational changes of the gate domain.

Semiconductor photocatalysis has attracted great interest because it provides a promising pathway for solving energy supply and environmental pollution problems. To date, various kinds of semiconductor materials, including metal oxides, 1 sulfides, 2 nitrides, 3 and their mixed solid solutions, 4,5 have been exploited as photocatalysts responsive to both the UV and visible light ranges. However, their applications are usually restricted by photocorrosion, short lifetimes of photogenerated electronÀhole pairs, and limited visible-light responses. 6 It is, therefore, of considerable significance to develop an efficient strategy toward producing catalysts with high photoactivity and high stability for practical applications.Although narrow-band-gap semiconductors are able to capture visible light in the solar spectrum, their photogenerated electronÀhole pairs suffer from fast recombination. Thus, tailoring semiconductor properties by fabricating designed structures is indispensable to improving the overall charge-transfer efficiency. For instance, reducing doping defects can suppress the recombination of photogenerated charge carriers, resulting in an improved photocatalytic activity. 7 In addition, combining a semiconductor with a metal or coupling two different semiconductors to form a heterostructure is another way to promote the separation of photogenerated charge carriers and thus increase their lifetime. 8,9 Heterostructure construction between two different semiconductors has been extensively exploited in many fields such as photocatalysis and solar energy conversion to enhance the performance of photovoltaic devices, 10,11 because heterojunctions dominate some behaviors of photogenerated charges, such as the direction of transportation, the distance for separation, and the recombination rate. 12,13 Furthermore, the internal electric field built at a heterojunction interface can greatly decrease the photogenerated charge-carrier recombination and increase the charge-carrier lifetimes, thus enhancing the photocatalytic activity. Therefore, heterostructure construction is not only a feasible approach for developing highly active photocatalysts response to visible light, but also a rational route to studying the relationship between photogenerated charge-carrier transfer and photocatalytic properties.Bismuth oxyhalides (BiOX, X = Cl, Br, and I) are well-known layered compounds that have a crystal structure of [Bi 2 O 2 ] 2+ layers interleaved by slabs comprising halide atoms. Owing to strong intralayer bonding and weak interlayer van der Waals interactions, these unique layered structures usually exhibit fascinating properties (e.g., anisotropic structural, electrical, optical, and mechanical properties) and have promising applications in cosmetics, pigments, catalysis, and photoelectrochemical devices. 14 In particular, bismuth oxyhalides are interesting as they offer the possibility to manipulate the electronic structure by choosing different halide atoms in the crystal structure, which is highly desirable fro...

The Escherichia coli uracil:proton symporter UraA is a prototypical member of the nucleobase/ascorbate transporter (NAT) or nucleobase/cation symporter 2 (NCS2) family, which corresponds to the human solute carrier family SLC23. UraA consists of 14 transmembrane segments (TMs) that are organized into two distinct domains, the core domain and the gate domain, a structural fold that is also shared by the SLC4 and SLC26 transporters. Here we present the crystal structure of UraA bound to uracil in an occluded state at 2.5 Å resolution. Structural comparison with the previously reported inward-open UraA reveals pronounced relative motions between the core domain and the gate domain as well as intra-domain rearrangement of the gate domain. The occluded UraA forms a dimer in the structure wherein the gate domains are sandwiched by two core domains. In vitro and in vivo biochemical characterizations show that UraA is at equilibrium between dimer and monomer in all tested detergent micelles, while dimer formation is necessary for the transport activity. Structural comparison between the dimeric UraA and the recently reported inward-facing dimeric UapA provides important insight into the transport mechanism of SLC23 transporters.

Showing MOFs' true colors: An iron‐based metal–organic framework, MIL‐53(Fe), is explored as an enzyme mimic with intrinsic peroxidase‐like activity. MIL‐53(Fe) can catalyze the oxidation of different peroxidase substrates in the presence of H2O2 (see graphic; TMB=3,3′,5,5′‐tetramethylbenzidine, OPD=o‐phenylenediamine), providing a new and simple colorimetric detection of hydrogen peroxide and ascorbic acid.