Crystallization and X-ray analysis of the transcription-activator protein C1 of bacteriophage P22 in complex with the PRE promoter element.

ABSTRACT: The transcription-activator protein C1 of the temperate phage P22 of Salmonella typhimurium plays a key role in the lytic versus lysogenic switch of the phage. A homotetramer of 92-residue polypeptides, C1 binds to an approximate direct repeat similar to the transcription activator CII of coliphage λ. Despite this and several other similarities, including 57% sequence identity to coliphage CII, many biochemical observations on P22 C1 cannot be explained based on the structure of CII. To understand the molecular basis of these differences, C1 was overexpressed and purified and subjected to crystallization trials. Although no successful hits were obtained for the apoprotein, crystals could be obtained when the protein was subjected to crystallization trials in complex with a 23-mer promoter

SUBMITTER: Mondal A 

PROVIDER: S-EPMC4601593 | biostudies-literature | 2015 Oct

REPOSITORIES: biostudies-literature