Bacteriophage T4 gene 45. Sequences of the structural gene and its protein product.

Bacteriophage T4 gene 45 codes for a protein whose functions are required for both T4 DNA replication and T4 late gene transcription. To facilitate studies of the interactions of 45 protein with the T4 DNA replication complex and with RNA polymerase, we have determined the primary structure of 45 protein. The amino acid sequence of 45 protein has been determined by correlating nucleotide sequence analysis of gene 45 with protein chemistry studies of 45 protein. Our studies indicate that gene 45 codes for a polypeptide containing 227 amino acids, with a calculated Mr = 24,710. The coding region of gene 46 is preceded by a putative promoter containing sequences which are homologous to Escherichia coli RNA polymerase recognition and binding regions. In addition, there are sequence similarities in the translation initiation regions of gene 45 and the rIIB gene, which may relate to their common regulation by regA protein.