Acidic carboxyl-terminal domain of gene 2.5 protein of bacteriophage T7 is essential for protein-protein interactions.

摘要: The product of gene 2.5 protein bacteriophage T7, a single-stranded DNA-binding protein, physically interacts with phage encoded DNA polymerase and primase/helicase proteins. A truncated (GP2.5-delta 21C) was constructed by in vitro mutagenesis lacks the 21 carboxyl-terminal amino acids found wild-type 15 which are acidic. GP2.5-delta 21C cannot substitute for vivo; not viable exhibit less than 1% synthesis observed phage-infected cells. has been purified to apparent homogeneity from cells overexpressing its cloned conformation that differs as judged circular dichroism spectra. Purified retains ability bind DNA; association constant DNA, determined nitrocellulose filter binding, is 3.2 x 10(6) M-1 identical protein. However, monomer solution, whereas exists dimer. does interact T7 measured affinity chromatography fluorescent emission anisotropy. mutant stimulate activity on primed templates.