Location of the T4 gene 32 protein binding site on polyoma virus DNA

A comparison of the phage T4 gene 32 protein and Escherichia coli RNA polymerase binding sites on hamster papovavirus DNA

Phage T4 gene 32 protein and Escherichia coli RNA polymerase were bound to hamster papovavirus DNA. The binding regions were identified by electron microscopy employing a protein-free spreading technique. After gene 32 protein treatment four denaturation regions could be mapped, at 0.04-0.12, 0.30-0.36, 0.50-0.60 and 0.75-0.90 DNA map units, respectively, using the unique BamHI cleavage site as zero point. Eight RNA polymerase binding sites can be found which are localized at positions 0.05; 0.11; 0.18; 0.31; 0.57; 0.66; 0.76 and 0.82. A comparison of the RNA polymerase binding sites with the gene 32 protein denaturation pattern reveals a correspondence of six of eight polymerase binding sites with (A+T)-rich regions within the hamster papovavirus genome.

The binding of T4 gene 32 protein to MS2 virus RNA and transfer RNA

Fluorescence titrations, absorption spectroscopy and stopped-flow techniques were used to study the interaction of T4 coded 32-protein (P 32) with MS2 RNA and total tRNA from E. coli under different ionic conditions. It is shown that the amount of MS2 RNA and tRNA secondary structure melted by P 32 varies markedly and reversibly within a range of ionic conditions under which the binding constant of P 32 to single-stranded nucleic acids unable to form stable hairpins remains higher than 10(8) M-1. Kinetic experiments suggest that P 32 dissociates from the MS2 RNA rewinding strand with a similar rate constant as calculated for the dissociation from single-stranded regions. Possible in vivo consequences of these findings are discussed.