Semiempirical quantum models are routinely used to study mechanisms of RNA catalysis and phosphoryl transfer reactions using combined quantum mechanical (QM)/molecular mechanical methods. Herein, we provide a broad assessment of the performance of existing semiempirical quantum models to describe nucleic acid structure and reactivity to quantify their limitations and guide the development of ne...

BACKGROUND AND OBJECTIVES Optical clearing agents (OCAs) have previously been shown to increase depth penetration within turbid tissue ex vivo. This paper quantifies tissue optical properties of the hamster cheek pouch model in order to provide a means to assess the effect of OCAs quantitatively in vivo. STUDY DESIGN/MATERIALS AND METHODS Diffuse reflectance spectra were obtained from both ch...

Nicotinate mononucleotide (NaMN):5,6-dimethylbenzimidazole (DMB) phosphoribosyltransferase (CobT) from Salmonella enterica plays a central role in the synthesis of alpha-ribazole-5'-phosphate, an intermediate for the lower ligand of cobalamin. In earlier studies it proved difficult to obtain the structure of CobT bound to NaMN because it is hydrolyzed in the crystal lattice in the absence of th...

A series of six analogs of phosphatidylserine (PS) was synthesized in which the conformational mobility of the backbone was limited. Each analog was a derivative of one of the three diastereoisomeric cyclopentane-1,2,3-triols, so that the glycerol moiety of the PS was, in effect, replaced by each cyclopentane-1,2,3-triol. Four of the members of the series were vicinal dipalmitates [1,2/3-(1P); ...

A bifunctional enzyme, consisting of 3-deoxy-n-arabinoheptulosonate 7-phosphate synthetase and chorismate mutase, has been purified to homogeneity from Bacillus subtilis. Ultracentrifugation revealed a single symmetrical peak of protein. A single protein band also was observed when the homogeneous preparation was subjected to polyacrylamide gel electrophoresis in the presence of sodium dodecyl ...

The light dependent energization of the thylakoid membrane was analyzed in isolated intact spinach (Spinacia oleracea L.) chloroplasts incubated with different concentrations of inorganic phosphate (Pi). Two independent methods were used: (a) the accumulation of [(14)C]5,5-dimethyl-2,4-oxazolidinedione and [(14)C] methylamine; (b) the energy dependent chlorophyll fluorescence quenching. The inh...