Purification and characterization of gene 17 product of bacteriophage T3

Tail fiber proteins of bacteriophage T3 are encoded by gene 17. By using in vitro complementation for phage assembly as an assay, the product of gene 17 (gp17) was purified to near homogeneity from cells infected with a double mutant of T3 defective in DNA synthesis and head assembly. The purified gp17 consists of a single polypeptide having a molecular weight of 67,000. Electron microscopy of the purified gp17 showed a fiber structure similar to the tail fiber in a virion. The subunit structure of the purified, native gp17 was analyzed by using a crosslinking agent, dimethyl suberimidate. The results indicate that native gp17 is a trimer of gp17 monomer.