RNA helicase A (RHA) is a highly conserved protein with multifaceted functions in the gene expression of cellular and viral mRNAs. RHA recognizes highly structured nucleotides and catalytically rearranges the various interactions between RNA, DNA, and protein molecules to provide a platform for the ribonucleoprotein complex. We present the first solution structures of the double‐stranded RNA‐binding domains (dsRBDs), dsRBD1 and dsRBD2, from mouse RHA. We discuss the binding mode of the dsRBDs of RHA, in comparison with the known dsRBD structures in their complexes. Our structural data provide important information for the elucidation of the molecular reassembly mediated by RHA. Proteins 2012;. © 2012 Wiley Periodicals, Inc.

The paddle-wheel type cluster Co(RCOO)(L) (R = substituent group, L = terminal ligand), possessing unusual metal coordination geometry compared with other cobalt compounds, may display high catalytic activity but is highly unstable especially in water. Here, we show that with judicious considerations of the host/guest geometries and modular synthetic strategies, the labile dicobalt clusters can be immobilized and stabilized in a metal-organic framework (MOF) as coordinative guests. The Fe(na)(L) fragment in the MOF [{Fe(μ-O)(bdc)}{Fe(na)(L)}] (Hbdc = 1,4-benzenedicaboxylic acid, Hna = nicotinic acid) can be removed to give [{Fe(μ-O)(bdc)}] with a unique framework connectivity possessing suitable distribution of open metal sites for binding the dicobalt cluster in the form of Co(na)(L). After two-step, single-crystal to single-crystal, postsynthetic modifications, a thermal-, water-, and alkaline-stable MOF [{Fe(μ-O)(bdc)}{Co(na)(L)}] containing the desired dicobalt cluster was obtained, giving extraordinarily high electrocatalytic oxygen evolution activity in water at pH = 13 with overpotential as low as 225 mV at 10.0 mA cm.

Purpose-To quantify the type, frequency and magnitude of artifacts in four-dimensional (4D) CT images acquired using a multislice cine method.Methods and Materials-Fifty consecutive patients, who underwent 4D-CT scanning and radiotherapy for thoracic or abdominal cancers, were included in this study. All the 4D-CT scans were performed on the GE multislice PET/CT scanner with the Varian RPM system in cine mode. The GE Advantage 4D software was used to create 4D-CT data sets. The artifacts were then visually and quantitatively analyzed. We further performed statistical analyses to evaluate the relationships between patient-or breathing pattern-related parameters and the occurrence as well as magnitude of artifacts.Results-It was found that 45 of 50 patients (90%) had at least one artifact (other than blurring) with a mean magnitude of 11.6 mm (range, 4.4 -56.0 mm) in the diaphragm or heart. We also observed at least one artifact in 6 of 20 lung or mediastinal tumors (30%). Statistical analysis revealed that there were significant differences between several breathing pattern-related parameters, including abdominal displacement (p < 0.01), for the subgroups of patients with and without artifacts. The magnitude of an artifact was found to be significantly but weakly correlated with the abdominal displacement difference between two adjacent couch positions (R = 0.34, p < 0.01).Conclusions-This study has identified that the frequency and magnitude of artifacts in 4D-CT is alarmingly high. Significant improvement is needed in 4D-CT imaging.

Converting CO into fuels via photochemical reactions relies on highly efficient and selective catalysts. We demonstrate that the catalytic active metal center can cooperate with neighboring hydroxide ligands to boost the photocatalytic CO reduction. Six cobalt-based metal-organic frameworks (MOFs) with different coordination environments are studied at the same reaction condition (photosensitizer, electron donor, water/organic mixed solvent, and visible light). In pure CO at 1.0 atm, the MOFs bearing μ-OH ligands neighboring the open Co centers showed CO selectivities and turnover frequencies (TOFs) up to 98.2% and 0.059 s, respectively. More importantly, their TOFs reduced only ca. 20% when the CO partial pressure was reduced to 0.1 atm, while other MOFs reduced by at least 90%. Periodic density functional theory calculations and isotope tracing experiments showed that the μ-OH ligands serve not only as strong hydrogen-bonding donors to stabilize the initial Co-CO adduct but also local proton sources to facilitate the C-O bond breaking.