Characterization of Adsorbed Molecular Water on the Surface of a Stretched Polytetrafluoroethylene Tape Analyzed by (1)H NMR.

A single molecule often exhibits a largely different material character from a bulk matter. Although a perfluoroalkyl (Rf) compound is a representative one, many interests have mostly been devoted to the bulk character only thus far, leaving the single molecular character unclear. Recently, a new theoretical framework, stratified dipole-arrays (SDA) theory, has appeared for comprehensive understanding of Rf compounds in terms of both single and bulk systems.

(1)H NMR Analysis of Water Freezing in Nanospace Involved in a Nafion Membrane.

Water involved in a polyelectrolyte membrane of Nafion has recently been revealed to comprise three distinctive molecular species with respect to molecular motion correlated with the hydrogen bonding structure by using (1)H NMR, infrared, and mass spectrometries. The three species are assigned to the condensed water, hydration water, and strongly bounded water on the sulfonic acid group. In the present study, on the contrary to an expectation on this schematic, even the condensed water is found unfrozen when the membrane is cooled down to -50 °C, and a freezing begins when it is cooled down to -60 °C or lower.

Hydration structure of strongly bound water on the sulfonic acid group in a Nafion membrane studied by infrared spectroscopy and quantum chemical calculation.

The hydration structure of the 'strongly bound water' around the sulfonic acid (SA) groups in Nafion, which has recently been revealed by (1)H NMR spectroscopy (Anal. Chem., 2013, 85, 7581), is studied using infrared spectroscopy with the aid of quantum chemical (QC) calculations.

The N-terminal region of influenza virus polymerase PB1 adjacent to the PA binding site is involved in replication but not transcription of the viral genome.

The influenza virus genome forms viral ribonucleoprotein (vRNP) complexes with nucleoprotein and viral RNA-dependent RNA polymerases (RdRp), PB1, PB2, and PA subunits. The vRNP complex catalyzes both genome replication and transcription reactions. PB1 contains the motifs highly conserved among RdRps and functions as a catalytic subunit of RdRp.

Involvement of the N-terminal portion of influenza virus RNA polymerase subunit PB1 in nucleotide recognition.

The influenza virus PB1 protein functions as a catalytic subunit of the viral RNA-dependent RNA polymerase and contains the highly conserved motifs of RNA-dependent RNA polymerases together with putative nucleotide-binding sites. PB1 also binds to viral genomic RNAs and its replicative intermediates through the promoter regions. The detail function and interplay between functional domains are not clarified although a part of structures and functions of PB1 have been clarified.