The temperature-dependences of the second-order rate constants (k) of the reactions of the catalytic site thiol groups of two cysteine peptidases papain (EC 3.4.22.2) and actinidin (EC 3.4.22.14) with a series of seven 2-pyridyl disulphide reactivity probes (R-S-S-2-Py, in which R provides variation in recognition features) were determined at pH 6.7 at temperatures in the range 4-30 degrees C b...

Abstract Use of abiotic chemical systems for understanding higher order superstructures is challenging. Here we report a ring‐in‐ring(s) system comprising hydrogen‐bonded macrocycle and cyclobis(paraquat‐ o ‐phenylene) tetracation ( ‐Box ) or p CBPQT 4+ , that assembles to construct discrete structures with adaptive conformation. As indicated by mass spectrometry, computational modeling, NMR sp...

An investigation of microscopic motional narrowing of nmrspectra of polycrystalline tetra-, tn-, diand mono-methylammonium chloride is reported. A diversity of rotational motions of the ions and of the methyl groups within the ions is exhibited. The problem of detailed interpretation of the line-narrowing is particularly acute for two of these compounds, and also for solid 1-valine. The proper ...

The contributions of backbone NH group dynamics to the conformational heat capacity of the B1 domain of Streptococcal protein G have been estimated from the temperature dependence of 15N NMR-derived order parameters. Longitudinal (R1) and transverse (R2) relaxation rates, transverse cross-relaxation rates (eta(xy)), and steady state [1H]-15N nuclear Overhauser effects were measured at temperatu...

background: there are two subclasses of human iga (iga1 and iga2) that differ in antigenic properties and in chemical composition. the constant domains of α1 and α2 heavy chains have >95% sequence homology though major structural differences exist in the hinge region. quantitation of iga subclass levels depends on the availability of monoclonal antibodies (mabs) specific for conserved conformat...

background: varicocele is associated with the failure of ipsilateral testicular growth and development, and the symptoms of pain and reduced fertility. the highly condensed structure of the sperm nuclear chromatin is provided by proper expression of transition nuclear protein (tnp) genes, so any dysregulational expression of these genes results in abnormal spermatogenesis and infertility. objec...

the results of mndo, am1 and pm3 semi-empirical calculations and hf/6-31g*, mp/6-31g*, mp2/6-311+g**, and b3lyp/6-311g** and qcisd/6-31g* ab initio methods for angle strain and conjugation effects in twist-boat, boat, and half-chair geometries of (z,z,z)-cycloocta-1,3,5-triene indicate that all methods, except pm3, predict wrong ordering of the conformations.

ab initio calculations at hf/6-31g* level of theory for geometry optimization and mp2/6-31g*//hf/6-31g*for total energy calculation are reported for z-cyclooctene (1). the most favorable conformation of 1 is theunsymmetric boat-chair (1-bc) geometry. potential energy profiles for two different boat-chair/boat-chairinterconversion processes were calculated. the process via a chair transition sta...