Characterization of RNA primer synthesis in the T4 bacteriophage in vitro DNA replication system.

摘要: Abstract In the presence of any natural single-stranded DNA, bacteriophage T4 gene 41 and 61 proteins catalyze synthesis a group pentaribonucleotides. These RNA molecules are homogeneous in chain length, but heterogeneous sequence. other five replication proteins, these pentaribonucleotides utilized with high efficiency as primers for de novo DNA initiations on lagging strand process. By using two-dimensional fractionation system plus variety enzymatic analyses, found to have either unique pppApC dinucleotide or pppG their starting residue, followed both cases by many different sequences. However, when containing glucosylated 5-hydroxylmethyl cytosine is used template, only pppApC-initiated class made. Alone, protein exhibits DNA-dependent GTPase (and ATPase) activity, nucleoside diphosphate inorganic phosphate products. blocking this activity synthetic GTP analogue, gamma S, we show that limited RNa primer can occur without nucleotide hydrolysis protein, prolonged requires such hydrolysis. This result, viewed light observations presented accompanying paper, suggests acts "mobile promoter," perhaps leaving perform actual polymerization termination functions