We have examined the actions of several amino group reagents on delayed rectifier potassium channels in squid giant axons. Three general classes of reagents were used: (1) those that preserved the positive charge of amino groups; (2) those that neutralize the charge; and (3) those that replace the positive with a negative charge. All three types of reagents produced qualitatively similar effect...

Aminoacylation of tRNA is an essential event in the translation system. Although in the modern system protein enzymes play the sole role in tRNA aminoacylation, in the primitive translation system RNA molecules could have catalysed aminoacylation onto tRNA or tRNA-like molecules. Even though such RNA enzymes so far are not identified from known organisms, in vitro selection has generated such R...

objective(s) motility plays a major role in pathogenicity of helicobacter pylori, yet there is  scarce data regarding its chemotactic behaviour. the present study was designed to investigate the chemotactic responses of local isolates of h. pylori towards various sugars, amino acids, as well as some other chemical substances. materials and methods chemotaxis was assayed by a modified adler’s me...

The postulated fragmentation of RNase by N-acetoxy-2fluorenylacetamide (N-acetoxy-2-FAA), an activated metabolite of the carcinogen, N-hydroxy-24iuorenylacetamide, has been investigated. The interaction of N-acetoxy-Z-FAA with RNase resulted in the formation of two new proteins separable from RNase by electrophoresis and ion exchange chromatography. These proteins contained no new NH2terminal a...

The free energies of hydration of the 20 amino acids in their zwitterionic form, their shifts and the side-chain free energies of a transfer have been calculated using the Ðnite di†erence PoissonÈBoltzmann methodology. A comparison of the results obtained with charge and size parameters from some popular force Ðelds used in modelling biomolecules is presented. The force Ðelds considered include...

In the present work, the structural and electronic properties, and conductivity of (5,5) and (6,6) Single Walled Carbon Nanotubes in the ground state have done by using the Hartree-Fock and density functional theory DFT-B3LYP/6-31G* level. Delocalization of charge density between the bonding or lone pair and antibonding orbitals calculated by NBO (natural bond orbital) analysis. These methods a...

Valence topological charge-transfer (CT) indices are applied to the calculation of pH at the pI isoelectric point. The combination of CT indices allows the estimation of pI. The model is generalized for molecules with heteroatoms. The ability of the indices for the description of molecular charge distribution is established by comparing them with the pI of 21 amino acids. Linear correlation mod...

The unimolecular decompositions of protonated heterodimers of native and derivatized amino acids to yield the protonated monomers were studied as a guide to charge location in peptide ions. Analyses using a hybrid instrument of BEqQ geometry demonstrated the advantages (with respect to mass resolution, sensitivityr reproducibility, and the elimination of extraneous signals) of the detection of ...