Deletions at the N terminus of bacteriophage φ29 protein p6: DNA binding and activity in φ29 DNA replication

Abstract

Deletions corresponding to the first 5 or 13 amino acids (aa), not counting the initial Met, have been introduced into the N terminus of the phage φ29 protein p6. The activity of such proteins in the in vitro φ29 DNA replication system, their capacity to interact with the φ29 DNA ends, and their interference with the wild type (wt) protein p6 activity have been studied. The initiation activity of protein p6 decreased considerably when 5 aa were deleted and was undetectable when 13 aa were removed. The mutant proteins were unable to specifically interact with the φ29 DNA ends. These results indicate the need of an intact N terminus for the activity of protein p6. However, such N-truncated protein inhibited both the specific binding of the wt protein p6 to the φ29 DNA ends and its activity in φ29 DNA replication.