Identification of DNA binding proteins in vaccinia virus by DNA-protein crosslinking.

DNA binding proteins of vaccinia virus (VV) virions, strain LIVP, have been studied by their covalent crosslinking to DNA, using two-dimensional gel retardation electrophoresis of crosslinked DNA and proteins as well as the 'protein image' hybridization assay. Five proteins with molecular masses of 16, 25, 27, 41 and 54 kDa, respectively, associated with all analysed DNA sequences, including early and late genes and their promoters, have been identified.

The accessibility of phage MS2 RNA to structure specific nucleases in various conditions.

The accessibility of ds- and ss-segments of phage MS2 RNA to ds- and ss-specific nucleases (RNase III, nuclease SV and nuclease S1) was studied. The results show that the RNA has hydrolysis sites for all the nucleases used. These sites are unvariable in a wide range of the conditions (ionic strength, pH, bivalent cations and temperature) and are not changed also after denaturation-renaturation of the RNA.

Reconstruction of tRNAPhe molecules from the fragments by linkage with T-4 RNA ligase in double-stranded regions.

Phenylalanine-specific tRNA from yeast was hydrolysed with cobra venom ribonuclease in the double-stranded regions and the fragments isolated. The 'dissected' molecules with nicks in positions 28 and 41 were reconstructed from supplementary fragments and treated with T-4 RNA ligase. A phosphodiester bond between two fragments was formed when the fragment combination (1-28) + (29-76) was used.

Comparison of the hydrolysis patterns of several tRNAs by cobra venom ribonuclease in different steps of the aminoacylation reaction.

The hydrolysis of several tRNAs by an endonuclease extracted from the venom of Naja oxiana and specific for double-stranded, or at least highly ordered, regions has been studied under various experimental conditions. It is shown that the hydrolysis patterns of yeast tRNAPhe, tRNAVal and tRNAAsp in the isolated state are similar, most of the cuts occurring in the anticodon and acceptor stems. Ionic conditions are able to modify the hydrolysis pattern.